Hewlett-Packard 3312A Function Generator Operating and Service Manual

 OPERATING AND SERVICE
MANUAL
MODEL 3312A
FUNCTION GENERATOR
Serial Number: 1432A01246
IMPORTANT NOTICE
If the Serial Number of your instrument is lower than the one on
this title page, the manual contains revisions that do not appiy to
your instrument. Backdating information given in the manual adapts
it to eartier instruments,
Where practical, backdating information is integrated into the text,
parts list and schematic diagrams. Backdating changes are denoted
by a delta sign. An open delta (A) or lettered delta {Aa} on a given
page, refers to. the corresponding backdating note on that page.
Backdating changes not integrated into the manual are denoted by
a numbered delta (44) which refers to the corresponding change in
the Backdating Section (Section VII).
| WARNING À
To help minimize the possibility of electrical fire or shock
hazards, do not expose this instrument to rain or excess
moisture.
Manual Part No. 03312-50603
Microfiche Part No. 03312-90053
Copyright Hewlett-Packard Company 1974
P.O. Box 301, Loveland, Colorado 80537 U.S.A.
Printed: April 1977
M
I
:
-
ta]
~3
3
=
ip; PACKARD
CERTIFICATION
Hewlett-Packard Company certifies that this instrument met its published
specifications at the time of shipment from the factory. Hewlett-Packard
Company further certifies that its calibration measurements are traceable to the
United States National Bureau of Standards, to the extent allowed by the
Bureau's calibration facility, and to the calibration facilities of other
International Standards Organization members.
WARRANTY AND ASSISTANCE
This Hewlett-Packard product is warranted against defects in materials and
workmanship for a period of one year from the date of shipment, except that
in the case of certain components, if any, listed in Section I of this operating
manual, the warranty shall be for the specified period. Hewlett-Packard will, at
its option, repair or replace products which prove to be defective during the
warranty period provided they are returned to Hewlett-Packard, and provided
the proper preventive maintenance procedures as listed in this manual are
followed. Repairs necessitated by misuse of the product are not covered by this
warranty. NO OTHER WARRANTIES ARE EXPRESSED OR IMPLIED,
INCLUDING BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF
MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
HEWLETT-PACKARD IS NOT LIABLE FOR CONSEQUENTIAL DAMAGES.
If this product is sold as part of a Hewlett-Packard integrated instrument
system, the above warranty shall not be applicable, and this product shall be
covered only by the system warranty.
Service contracts or customer assistance agreements are available for
Hewlett-Packard products.
For any assistance, contact your nearest Hewlett-Packard Sales and Service
Office. Addresses are provided at the back of this manual.
Model 3312A
Section |
SECTION |
GENERAL
1-1. INTRODUCTION.
1-2. This manual contains installation procedures, oper-
ating instructions and maintenance information for the
Model 3312A Function Generator. Instrument specifica-
tions and procedures for adjusting the instrument to those
specifications, schematic diagrams, theory of operation, and
troubleshooting information are provided for use in main-
taining the instrument.
1-3. This section of the manual contains a description of
the Model 3312A, the performance specifications and
characteristics, and instrument identification information.
1-4, DESCRIPTION.
1-5. The Hewlett-Packard Model 3312A Function Genera-
tor is a compact, wide range, dual function generator
consisting of a main generator and 4 modulation generator.
The main generator provides sine, square, or triangle wave
outputs over the frequency range of 0.1 Hz to 13 MHz. The
modulation generator produces sine, square and triangle
waveforms with a frequency range of 0.01 Hz to 10 kHz.
The modulation generator can be used to Amplitude
Modulate (AM) or Frequency Modulate (FM) the output
signal of the main generator. The AM envelope can be
adjusted from 0% to 100%; FM can change the carrier
frequency up to * 5%.
1-6. SWEEP QUTPUT,
1-7. For added versatility, the 3312A has a built-in sweep
generator which can be used to sweep the frequency of the
main generator. The frequency of the main generator can
be swept as much as 100:1 on any range.
1-8. OUTPUT LEVEL.
1-9. The output voltage of the 3312A can be varied from
OV to 10 V peak-to-peak into 50 ohms in four voltage
ranges. A front panel control permits continuous adjust-
ment within each voltage range. The dc level of the main
generator output can be adjusted within the range of
£ 10 volts using the front panel offset control. With the
OFFSET in the CAL position the de offset is eliminated.
INFORMATION
1-10. BURST.
1-11. The burst is either a single pulse or a series of pulses
which are rear panel selectable by-a slide switch labeled
SINGLE and MULTIPLE. The TRIGGER PHASE control
adjusts the phase of the signal. FREE RUN disables the
burst.
1-12. SYMMETRY.
1-13, The main and the modulation generators have sep-
arate front panel symmetry adjustments which will vary the
symmetry of the output waveforms. The CAL position of
each SYM knob will produce symmetrical waveforms. In
the SWEEP mode, the SYM adjusts the sweep rate, and
CAL selects a 90:10 ramp.
1-14. SPECIFICATIONS.
1-15. Table 1-1 is a complete list of the Model 3312A
critical specifications. These specifications are the perfor-
mance standards or limits against which the instrument can
be tested. Table 1-2 lists some supplemental performance
characteristics which are not specifications, but are typical
characteristics included as additional information for the
user.
1-16. Any changes in specifications due to manufacturing,
design or traceability to the U.S. National Bureau of
Standards are included in Table 1-1 of this manual.
Specifications listed in this manual supersede all previous
specifications for the Model 3312A.
1-17. INSTRUMENT AND MANUAL IDENTIFICATION.
1-18. The instrument serial number is located on the rear
panel. Hewlett-Packard uses a twosection serial number
consisting of a four-digit prefix and a five-digit suffix. A
letter between the suffix and prefix identifies the country
in which the instrument was manufactured (A = USA, G=
West Germany, J = Japan, U = United Kingdom). All
correspondence with Hewlett-Packard should include the
complete serial number.
1-19. If the serial number of your instrument is lower than
the one on the title page of this manual, refer to Section
VII for backdating information that will adapt this manual
to your instrument.
1-1
Section |
Model 3312A
Table 1-1. Specifications.
FREQUENCY CHARACTERISTICS.
Dial Accuracy: + B% of full scale {After 1-hour warm-up.
Square Wave Rise or Fall Time (10% to 90%): < 18 nsec at full
rated output.
Aberrations: < 10%.
Triangle Linearity Error: < 1% of rated amplitude at 100 Hz.
Variable Symmetry: 30:20 to 20:80 to 1 Mz,
Spectral Purity:
Sine Wave Distortion: < 05% THD from 10Hz to 50 kHz.
> 30 dB below fundamental from 50 kHz to 13 MHz.
OUTPUT CHARACTERISTICS.
Impedance: 50 £2 + 10%.
Level: 20 V p-p into open circuit, 10 Y p.0 into 50 D.
Level Flatness (Sine Wave): + 3% from 10 Hz to 100 kHz at
full rated output {1 kHz reference}, < + 10% from 100 kHz
to 10 MHz at full rated output.
Step Attenuator Accuracy: better than 5%,
Sync Output: impedance: 50 Q + 10%, > 1 V p-D square wave
into open circuit,
Rise or Fall Time (10% to 90%): < 10 nsec.
DC Offset: + 10 volts maximum {subject to coarse amplitude
attenuator setting).
MODULATION CHARACTERISTICS.
Internal Modulation Source
Output Level: > 1.0 V p-p ито 10 Ка.
Spectral Purity: Sine Wave Distortion: < 2% THD from
10 Hz 10 10 kHz.
Amplitude Modulation
Carrier 3 dB Bandwidth: < 100 Hz to > 5 MHz.
Carrier Envelope Distortion: < 2% at 70% sine wave modula-
tion with fo = 1 MHz, f.q = $ kHz,
External Sensitivity: < 10 Y p-p for 100% modulation.
Frequency Modulation: + 5%,
Deviation: 0 to 5% (internal).
Modulation Frequency:
Internal: 0.071 Hz to 10 kHz.
External: DC to > 50 kHz,
Distortion: < -35AdB at fo = TOMHZ, fue = 1 kHz, 10%
modulation,
Sweep
Ramp Linearity Error: << 1% at 100 Hz,
EXTERNAL FREQUENCY CONTROL.
Input Requirement: With dial set to 10, application of O to - 7 V
de + 20% to the VCO input will linearly decrease frequency
by more than 1000:1. An ac voltage will FM the frequency
about a dial setting within the limits of (1<f<10) x range
setting.
Linearity: The frequency vs voltage curve will be linear within
0.5% over a 100:1 frequency range,
Table 1-2. General Information.
MAIN GENERATOR CHARACTERISTICS,
General:
Sine, Square, triangle, ramp, and pulse,
Variable Symmetry.
Range is 80:20 to 20:80,
rreguency Characteristics
Range: 0,1 Hz to 13 MHz in 8 decade ranges.
Output Characteristics
Attenuator: 1:1, 10:1, 100:1, 1000:1 and > 10:1 continuous
control,
MODULATION CHARACTERISTICS.
General:
External AM, FM, Sweep, Trigger, Gate or Burst.
Amplitude Modulation:
Repth: G to 100%,
Modulation Frequency: 0,01 Hz to 10 kHz (internal),
DC to > 1 MHz (external).
Types: Internal AM, FM, Sweep, Trigger, Gate or Burst,
Frequency Modulation:
Moduiation Frequency: 0,01 Hz to 10 kHz (internal).
DC to > 50 kHz {external}.
Sweep Characteristics
Sweep Width: < Range: 100:1 on any range.
Sweep Rate: 80:10 ramp, (0 Hz provides manual setting of
“Sweep Start” without Modulation Generator oscillating}.
sweep Mode: Repetitive linear sweep between start and stop
frequency settings. Retrace time can De increased with
symmetry control,
Gate Characteristics
Frequency Range: 0.1 Hz to 1 MHZ {useful to 10 MHz),
Start/Stop Phase Range: + 90” to -80”.
Gating Signal Frequency Range (External): DC to 1 MHZ.
(TTL compatible input level.)
External Frequency Control
Range: 1000:1 on any range.
General:
Operating Jemperature: 0°C to + 55°C: specifications apply
from 0°C to 40°C.
Storage Temperature: - 40° C to + 75° С.
Power: 100/120/220/240 \ + 5%, - 10%, switchable; 48 Hz
to 440 Hz; << 25 VA.
1.2
Model 3312A
Section Il
SECTION Il
INSTALLATION
2-1. INTRODUCTION,
2-2. This section explains how to prepare the Model 3312A
Function Generator for use. Included are initial inspection
procedures, power and grounding requirements, environ-
mental information, mounting instructions and instructions
for repackaging for shipment.
2-3. INITIAL INSPECTION.
2-4. This instrument was carefully inspected both mechani-
cally and electrically before shipment. If the shipping
container is damaged it should be kept until the contents of
the shipment have been checked mechanically and electri
cally. If the instrument does not pass a mechanical
inspection or the electrical performance tests given in
Section V, notify the carrier and refer to the warranty on
the front cover of this manual.
2-5. POWER REQUIREMENTS,
2-6. The Model 3312A can be operated from any source of
100, 120, 220 or 240 volts ac + 5% —10%, of 48 Hz to
440 Hz frequency. The instrument can be easily adapted to
the available line voltage by changing the position of the
slide switches on the rear panel.
2-7, Figure 2-1 illustrates the standard power plug config-
urations that are used throughout the United States and in
other countries. The -hp- part number shown directly below
each plug drawing is the part number for a 3312A power
cord equipped with the proper plug. If the appropriate
power cord is not included with the instrument, notify the
nearest Hewlett-Packard office and a replacement cord will
be provided.
8120-1351 5120-1368
8120—1689
2500 — ВА *
ATI
= USE 2
ae à
Yu à
5120-0698
8120-1248 8”
S1D-8B-4195
YUL LISTED FOR USE IN THE UNITED STATES OF AMERICA
Figure 2-1. Power Plugs.
2-8. GROUNDING REQUIREMENTS.
2-9. For the safety of operating personnel, the instrument
must be grounded. The offset pin on the power cable
grounds the instrument when plugged into the proper
receptacle.
2-10. INSTRUMENT MOUNTING.
2-11. Bench Use,
2-12. The front of the 3312A may be elevated for
operating convenience by flipping down the bails which are
attached to the two front feet of the instrument.
2-13. REPACKAGING FOR SHIPMENT.
2-14. The following paragraphs contain a general guide for
repackaging the instrument for shipment, Refer to Para-
graph 2-15 if the original container is to be used or 2-16 if
it is not. Ii you have any questions, contact the nearest -hp-
Sales and Service Office (see Appendix A for office
locations).
NOTE
If the instrument is to be shipped to Hewlett
Packard for service or repair, attach a tag to the
mstrument identifying the owner and indicating
the service or repair to be accomplished. In-
clude the model number and full serial number
of the instrument. In any correspondence,
identify the instrument by model number and
full serial number.
2-15. Place instrument in original container with appropri-
ate packing material and seal well with strong tape or metal
bands. If original container is not available, one can be
acquired from your nearest -hp- Sales and Service Office.
2-16. If original container is not to be used, proceed as
follows:
a. Wrap instrument in heavy paper, or plastic before
placing in an inner container.
b. Place packing material around all sides of instrument
and protect panel face with cardboard strips.
c. Place instrument and inner container in a heavy
carton or wooden box and seal with strong tape or metal
bands.
de. Mark shipping container “DELICATE INSTRU-
MENT,” “FRAGILE,” etc.
2-1
Model 33124
Section HI
SECTION Hi
OPERATING
31. INTRODUCTION.
3-2. This section contains complete operating instructions
for the Model 3312A Function Generator. Included is a
brief description of the instrument, a description of
controls and connectors, general operating information, and
a basic operating procedure.
3-3. DESCRIPTION.
3-4. The 3312A Function Generator combines (wo sepa-
rate function generators in one instrument -a main genera-
tor and a modulation generator. The frequency range of the
main generator is 0.1 Hz to 13 MHz in eight decade ranges.
The modulation generator frequency range is 0.01 Hz to
10 kHz. Both the main generator and the modulation
generator provide sine, triangle, square, pulse and ramp
outputs. The symmetry of all waveforms can be varied over
a range of 80:20 to 20:80 on the main generator and is set
at 10:90 on the modulation generator.
3-5. The main generator can be modulated or triggered by
the modulation generator to provide AM, FM, sweep or
burst. The main generator can also be modulated by an
external source connected to the MOD connector on the
modulation generator. The frequency of the main generator
can be externally controlled by applying an ac or de voltage
to the VCO input.
3-6. The output attenuator has a range of more than
1000:1 so that output levels ranging from I mV p-p to
10 V p-p into 50 ohms can be obtained.
3-7. The 3312A has a dc offset capability which allows the
de operating point of the main generator output to be
adjusted from - 10 V to + 10 V dc (as long as the dc offset
plus instantaneous ac does not exceed £ 10 V). The dc
offset can be adjusted using the front panel OFFSET
control or set to OV by pushing the associated CAL
button.
3-8. CONTROLS AND INDICATORS.
3-9. Figures 3-1 and 3-2 illustrate and describe the function
of all front and rear panel controls, connectors and
indicators. The description of each item is keyed to the
drawing within the figure,
3-10. GENERAL OPERATING INFORMATION.
3-11. Grounding.
3-12. To protect operating personnel, the 3312A chassis
must be grounded. All Hewlett-Packard instruments are
equipped with a three-conductor power cord, which, when
INSTR
UCTION
plugged into the proper receptical, grounds the instrument.
The offset pin of the power plug is the ground connection.
All input and output commons are connected directly to
outer chassis (frame) ground through the offset pin on the
power cord.
The outer shells of all input and output BNC
jacks are connected to the chassis. To protect
the operator from electrical shock, DO NOT
float this instrument.
3-13. Main Generator Outputs.
3-14. The main generator has two outputs, a main signal
output and a sync output. The main signal output (labeled
V p-p) provides the sine, square and triangle outputs. The
sync output (Paragraph 3-19) provides a pulse which can be
used for external timing purposes. Both outputs are BNC
connectors located on the front panel of the instrument.
3-15. Main Signal Output
3-16. The output of the main generator is de coupled to
supply both ac and de components of the output wave-
form. The main generator output level is 10 V p-p into 50
ohms. The SYNC output level is .25 V p-p into 50 ohms.
Output impedance of both outputs is SO ohms nominal.
3.17. Connections to this output should be made using
shielded cables equipped with BNC connectors. Table 3-1 is
a list of recommended -hp- cables. In order for the 3312A
to meet the specifications listed in Table 1-1, the main
signal output must be terminated into 50 ohms. The -hp-
Model 11048C 50 ohm Feedthru Termination is recom-
mended. Always place the termination at the load end of
the transmission line.
Table 3-1. Cable Assemblies.
10502A 9” Cabie Assembiy
11086A 24” Cable Assembly
t1O519A 72” Cable Assembly
3-18, SYNC Output.
3-19. The SYNC output supplies a one volt rectangular
wave which is 180° out of phase with the main generator
output signal. The leading edge and the trailing edge of the
SYNC pulse occur at the zero crossing point of the output
waveform. The frequency and duty cycle of this pulse vary
with the main output signal.
3-1
Section HI
Model 3312A
© © © © о © со
©
9
2
esr rE
я 13312; FUNCTION GENERATOR
INE RANGE Hz ENCON “Sur TION
ofi Е 10 100 1k OK 100k IM м FM me
FREQUENCY OUTPUT LOFFSETONLS : ait OUT CT EXT: ALL OUT =
OFFSET AMPLITUDE SYM a RANGE Hz
È YER SER & CAL VERMIER
FREES RUN
¿dd ded
LINE: 518 switch applies or removes ac power, The green
LED is lit when ON,
RANGE Hz: S1 through $8, pushbuttons select frequency
range, RANGE selection times the reading on the FRE.
QUENCY dial determines the output frequency of the
“ main generator,
FUNCTION: Interiocked buttons select one of three
functions. When they are all out, the dc level may be set
accurately (88,810, S11).
FREQUENCY: Sets the desired frequency within the
range of any of the RANGE pushbuttons,
OFFSET: R616 sets me de operating point of any
function, CAL position removes the de offset. Ese + Ege
must be tess than 10 V or clipping of the waveform will
ocour,
AMPLITUDE: 822, R613{a), (b}, adjust the peak-to-peak
amplitude of the waveform. It is attenuated in steps of
1:1, 10:1, 100:1, 1000:1; the VERNIER adjusts from
zero to maximum output voits for the particular range
selected,
SYM: RODS varies the symmetry of output waveforms
and the SYNC output. CAL is symmetrical.
D . -
SYNC: A square wave 180 out of phase with the main
generator. Useful for synchronizing external instruments
or driving a counter,
OUTPUT: Terminal for all main generator functions,
20 \М р-р into open circuit or 10 V р-р into 50 ohms, in
the 1:1 attenuator position,
ET
© © © © ©
© ©
© ©
TRIGGER PHASE: R615 sets the starting phase of the
output signal in the burst mode. FREE RUN disables the
burst,
AM: Selects amplitude modulation. Functional for inter-
nal or external modulation.
FM: 813 selects frequency modulation, Functional for
internal or external modulation,
SWF: 814 selects sweep mode. This function overrides
AM and FM.
~ WW Tl, : 815, $16, S17 select the modulating
function, External modulation is possible when all but-
tons are out, and the modulating signal is applied to the
MOD INT-EXT jack,
% AF START: R612 selects the percent of AM, the
deviation in FM, or the start frequency of the SWP.
RANGE Hz: R802, 821 select one of the three ranges of
modulating frequencies with continuous control within
each range via the VERNIER, The 0 position is used to
set the start sweep frequency.
MOD INT-EXT: Input for external AM or EM, Waveforms
of the modulation generator are also available at this
output when internal modulation is used,
SYM: R601 маме; the symmetry of the modulation
output waveform, CAL selects a 90:10 ramp for SWP and
symmetrical for all other functions,
3-2
Figure 3-1.
Front Panel,
Model 3312A
Section lil
—
SINGLE — MULTIPLE
TRIGGER
(+) | ин 100 М
20 \ —
250 т АТ
ты -10
ELISE E
125 т АТ L LL] +5% J
240 —d
bata PLINY
nv 48~66HZ 25VA MAX
33122-023963 |
SINGLE/MULTIPLE: S19 selects single cycle or multiple
cycles in the hurst mode.
TRIGGER: S20 selects either an interna! or external
trigger,
EXTERNAL TRIGGER INPUT: for externa! burst con-
trod,
VCO: Input for an external freguency control voltage
{Paragraph 3-66].
© © © ©
FUSE: F1 protects the instrument from current over-
loading.
100/120/220/240: 823, 824 slide switches to match the
instrument to ac line voltage being used,
PONER RECEPTACLE: Primary power is connected to
the instrument vía the power cord,
Figure 3-2. Rear Panel.
By connecting the SYNC output to the input of an
appropriate frequency measuring device, the output fre-
quency can be set with greater accuracy and resolution. The
SYNC output can also be used to trigger an oscilloscope or
synchronize an external oscillator.
3-206. Input Constraints.
3-21. The 3312A inputs and outputs are dc coupled. The
maximum instantaneous ac plus dc voltages which can be
safely applied to the inputs are + 10 Y. In some applica-
tions it may be necessary to connect one of the 33124
outputs to an ac or dc source node in a circuit. In these
cases, the de plus instantaneous value of external signal
level applied to the 3312A outputs must not exceed
+ 10 V.
Exceeding input or output voltages of +10 Y
{dc plus instantaneous ac) can cause damage to
the input or output circuitry of the 33124.
3-22. Modulation Generator Input/Output.
3-23. The BNC connector of the modulation generator
(labeled MOD) serves as both an input and an output. The
waveforms from the internal modulation generator (sine,
square or triangle) are available at the MOD connector and
are useful for synchronizing an oscilloscope when using the
AM, FM, or sweep modes. When none of the modulation
generator’s function buttons is pressed, an external modula-
tion source can be applied through the MOD connector.
Refer to Paragraph 346 for information concerning exter-
nal operation.
3-24. The modulation generator input/output is dc coupled
and the impedance is a nominal 8 kilohms. Refer to Table
3-1 for recommended cable assemblies to use with the
modulation generator.
3-25. Qutput Characteristics.
3-26. The main generator and the modulation generator
supply five different output waveforms.
a. Sine
b. Square
Cc. Triangle
d. Ramp
e. Pulse
3-3
Section [il
3-27. Sine Wave Output.
3-28. The Total Harmonic Distortion (THD) of the main
sine wave, including spurious and harmonics, is less than
0.5% from 10 Hz to 50 kHz and greater than 30 dB below
fundamental from 50 kHz to 13 MHz. The modulation sine
wave distortion is less than 2% THD from 10 Hz to 10 kHz.
3-28, Square Wave Output.
3-30. The RMS value of a symmetrical (50% duty cycle)
square waveform is equal to its peak value. The rise or fall
time is less than 18 nanoseconds between the 10% and 90%
points of the p-p output square wave. The abérrations, or
deviations from the final settling amplitude of the square
wave after overshoot, will not vary more than + 10% of the
final value.
3-31. Triangle Output.
3-32. The RMS value of the triangle waveform is 0.557
times the peak value. The triangle ramp will not deviate
from a straight line any more than 1% of the total
peak-to-peak value of the ramp. Nonlinearity is, therefore,
negligible.
3-33. Ramp.
3-34, A ramp output can be obtained from the main
generator by selecting the triangle waveform and adjusting
the symmetry control knob. The ramp output of the main
generator can be varied in amplitude with the AMPLITUDE
knob. The ramp output of the modulation generator has a
fixed amplitude, however, the slope or retrace time can be
varied with the SYM knob on the modulation generator.
3-35. Pulse,
3-36. A pulse with a variable amplitude from O V to 20 V
p-p into an open circuit, is possible with the main
generator. This involves selecting single cycle burst set to
start at the zero point with the TRIGGER PHASE knob,
and determining the pulse width with the FREQUENCY
dial. The SYNC output can deliver a <10 nsec rise time
puise by changing the symmetry of the main generator.
3-37. Gate or Burst.
3-38. The usable frequency range of the burst function is
from 0.1 Hz to 10 MHz. The trigger phase can be started
anywhere from - 80° to +90°. The stop will be at that
point at the termination of the burst (see Figure 3-3).
3-39. AM.
3-40. The Main Generator output can be amplitude modu-
lated up to 100%. The modulation frequency ranges from
0.01 Hz to 10kHz. Any of the modulation generator’s
functions can be used to AM.
3-4
Model 3312A
+ 10—
спрей:
START =
— 10) —
331288 3964
33124-893964
Figure 3-3. Phase Control of Burst,
NOTE
The 33124 is capable of > 100% modulation,
le., the strength of the modulating signal can be
greater than needed to just bring the carrier
level to zero, Overmodulation may cause distor
tion of the modulating information,
3-41. The extent of the amplitude variation is expressed as
the percentage of modulation. The following formula
defines the relationship between Fc and Fm (see Figure
3-4),
Emax - Fo X 100 = percent modulation
= — НЫЫ die ны кн AA See rem mp—
, fe,
SIRO
AVERAGE AMPLITUDE
Figure 3-4, Percent Modulation.
Model 3312A
3-42. FM.
3-43. The frequency of the main generator can be varied
up to + 5% by the modulation generator. The modulation
frequency can be set from 0.01 Hz to 10 kHz, and any of
the modulation waveforms can be used to FM.
3-44. SWP,
3-45. When the SWP button is pressed, the modulation
generator produces a linear ramp which sweeps the fre-
quency of the main generator. With the RANGE Hz knob
in the 0 Hz position, the “Sweep Start” frequency can be
et. The stop frequency, or the frequency at which the
sweep terminates, is set with the main frequency dial. The
rate of sweep is governed by the SYM knob.
3-46, External Contrel.
3-47. The front panel MOD INT-EXT input/output con-
nector is to be used for external amplitude modulating or
frequency modulating the main generator. For AM opera-
tion, an external input of less than 10 V p-p will give 100%
modulation. For FM operation, the external frequency may
be varied from dc to greater than 50 kHz. The AM and FM
pushbuttons must still be used.
3-48. The frequency of the main generator can be tuned
remotely by applying 0 V to - 2 Y dc to the VCO connector
on the rear panel. With the dial set to 10, any range can be
varied over the entire dial range within the limit set by the
range pushbuttons. Frequency modulation can also be
accomplished by applying an ac voltage to the VCO
terminal. Simultaneous AM and FM is possible with the
VCO input used to vary frequency and the MOD input used
for the AM signal.
3-49, Frequency.
3-50. The frequency range of the main generatoris 0.1 Hz
to 13 MHz in eight overlapping ranges. The dial accuracy is
+ 5% of full scale which means that the greatest accuracy
will be obtained at the high end of the dial. For instance, if
the dial were set to “1” on the 1 kHz range, the output
frequency would be | kHz £650 Hz. If, on the other hand,
the dial were set to “107 on the 100 Hz range, the output
frequency would be 1 kHz + 65 Hz.
3-51. The frequency range of the modulation generator is
0.01 Hz fo 10 kHz. The RANGE Hz knob selects the upper
frequency limit and the VERNIER is used to select
frequencies within the selected range.
3-52. Amplitude,
3-53. The amplitude of the main generator can be adjusted
from 0 to 20 V p-p into an open circuit or from 0 to 10 Y
p-p into 50 ohms. Amplitude of the modulation generator
is fixed at 1 V p-p into an open circuit, except | in SWP
operation (Paragraph 3-45).
Section HI
3-54. BASIC OPERATING PROCEDURES.
3-55. Instrument Turn-On.
a. Check the line voltage at the point of installation.
b. Refer to Figure 3-5. Set the rear panel Line Selector
switches to the setting that corresponds with the line
voltage to be used. Line voltage must be within - 10% to
+ 5% of the selected voltage setting. Line frequency must
be within the range of 48 Hz to 66 Hz.
pom. 100) Y ——— Line
120 У — Voltage 51 52
| | 100 Left Left
A +5%! 120 Right Left
240 — 220 Left Right
2209 Y mm 240 Right Right
Figure 3-5, Line Selector Switches,
c. Verify that the proper fuse is installed in the rear
panel fuse holder.
Line Setting Fuse Type -hp- Part No.
100 V/120 V 25 A250V Slo Blow = 2110-0201
220 Y 240 Y .125 Y 250 Y Sio Blow 2110-0318
d. Connect the detachabie ac power cord to the rear
panel power receptacie.
e. Set the LINE switch to the ON position, The green
light will illuminate.
3-56. Fuse Replacement.
3-57. The main ac line fuse is located on the rear panel
next to the line power receptacle. Remove the line power
cord before attempting to remove the fuse. Figure 3-6
shows how to replace the fuse.
— POWER CORD RECEPTACLE
— FUSE
| a
FUSE RECERTACLE
—— FUSE HOLDER
3312AB-3975
Figure 3-6. Fuse Replacement.
3-5
Section HI
358. Main Generator Operation.
3-39. The sine triangle and square waveforms, selected with
interlocking pushbuttons, are available at the BNC output
jack. The RANGE Hz pushbuttons and frequency dial
select frequencies from 0.1 Hz to 13 MHz in eight over-
lapping ranges. The frequency dial scale must be multiplied
by the RANGE Hz setting to obtain the frequency.
3-60. With the AMPLITUDE knob in the 10 position and
no load, a 10 volt peak signal is selected. The VERNIER
control adjusts the voltage from greater than 10 volts to 1
volt at that setting. In the 1 position the voltage is
adjustable from 1 volt to .1 volts; in the .1 position the
voltage is adjustable from .1 volts to .01 volts; and in the
‚01 position from .01 volts to O.
3-61. The symmetry of any waveform can be varied with
the SYM knob. The square waveform can be varied from
symmetrical to a ratio of 80:20 to 20:80 up to 1 MHz,
3-62. OFFSET changes the dc level of the waveform. The
CAL button eliminates dc offset. The peak ac voltage plus
the de offset should not exceed 10 V to avoid clipping of
the output waveform.
3-63. Burst,
3-64. With the rear panel TRIGGER switch (2) set to INT,
the upper slide switch (1) set to either SINGLE or
MULTIPLE, and TRIGGER PHASE (10) out of the FREE
RUN position, internal burst is initiated. The TRIGGER
PHASE knob controls the starting and stopping phase of
the output waveform. The SINGLE-MULTIPLE switch
selects a single cycle or multiple cycles respectively. Pulses
are obtained only when the square wave function is pushed.
Model 3312A
MERCURY Y о
)
od
Figure 3-7. External VCO.
The pulse width is set by the main generator's FRE-
QUENCY dial and the modulation generator’s RANGE Hz
knob sets the repetition rate. The TRIGGER PHASE knob
in the FREE RUN position disables the burst (see Figure
3-11 for burst operation).
3-65. With the rear panel slide switch (2) set to EXT, an
external burst may be applied in either single or multiple
cycles. TRIGGER PHASE is still operational. The external
gating signal frequency range is from de to 1 MHz. The
Шри! voltages must be TTL compatible.
3-66. VCO.
3-67. A dc voltage from O V to - 2 V applied to the rear
panel VCO connector is sufficient to vary the frequency of
the main generator over three decades. Since some dc
power supplies induce some noise, a supply similar to
the one in Figure 3-7 works well.
3-68. Modulation Generator Operation.
3-69. Figures 3-8 through 3-10 are operating illustrations
containing step-by-step operating procedures indexed to the
PINE RANGE dy РО КОТОМ X
oO 4 ! oo 1 lon aed LM L
00 a.
FRED yo ARE
OFFSET *ameyiTyDe SYM
. Press AM pushbutton.
. Select a function.
. Set the percent medulation,
. Set the modulation frequency.
. SYM in the CAL position.
Nd {aha =
AM with sine wave
AM with square wave
Figure 3-8,
3-6
AM Operation.
Section HI
Model 3312A
illustrations. The figures describe the operations to be sequence given, as succeeding steps may depend on control
accomplished in achieving the different modes of operation. settings and results of previous steps. In all cases, it is
assumed that the main generator is set to the frequency and
amplitude desired and that all modulation generator func-
3-70. The operating procedure must be performed in the tion pushbuttons are in the OUT position.
2
. Press FM pushbutton,
2. Select a Function,
3. Set the desired deviation of frequency,
- 722 FUNCTION GMNÁRATOR 4. Set the frequency of the change.
OR A E 16 1. TE or abc 1M „POT x a TA 5, SYM in CAL position.
НОО ООО A ;
eager OUTPUT PETESELGALT La RES
PE Fag T AMPLE SYM
KL HER al
eE IA
>
: Os
Loi
9: On
TRIGGER
SYNC PHASE
Cas e—-6 6 IN
Mieèh E NL у
(7) 1. Set stop frequency,
LE
CUTE
}
Figure 3-9, FM Operation.
— MZA FUNLTIGN GENESATOR 2. Press SWP button,
oF Oa 1 t 15 Arne Ae moe TM МД aM MODA ATION м 3. Set RANGE Hz to 0.
Ma On Г 50 SOC С С) О 4, Set start frequency.
FREQUENCY ou Cimarrón ses on i e NT 5. Sex RANGE Hz and VERNIER for desired repetition
Y o OFFSET “ampLTUDE SYM RANGE #2
EY 8 ren т ner rate.
Ae 6. Adjust retrace Hi
А. Lava Ale o * Jus F race ne
E 5 |
“e 7 J YRC w= в E
; a . ` an —_# —
bre 02907 =
Figure 3-10. Sweep Operation.
Section HI
Model 3312A
IIA FUNCTION GENERATOR
LIE RANGE Hj Fusion MOT LATIN
of O Lt 1 на to ля ‘Qu GOR CNW u La La a" wh +
100000000 SA
LI dl Li —
FREQUENCY CUTE LET LITO The wy, АЛЫЕ PE
DEFSET ANEP ETUDE Er PAGE Hr
We ENS ER Ben
A
Fp
a :
ES "a "Ez TN, PEN 7 N
Ca TNE U
pe
po \ ,
Г O) | TR:GGER
x i : :
* NT ЙО YE vamp PHASE
чи” A : >
fl Los: MER HUN en
Tre Ea A
"==
MULTIFLE
© ©
THAA-BADRE
1, Set rear panel siide switch to INT.
2.
slide switch,
Rotate TRIGGER PHASE clockwise to desired phase.
Set frequency of burst.
Set repetition rate,
na 52
NOTE The phasa of the square function is
TRIGGER PHASE.
В IE
ny e nt 0
Rael TE A
E
TRIGGER PHASE fully CW, SINGLE mode.
Select either MULTIPLE or SINGLE with rear panel
‘unaffected by
E
Ge
2
О E
+
PET
e
Repetition rate varied, MULTIPLE.
me on
hE
meurs:
Ня
=
HAE EEE
ut
pénis
== qe = - we
Ч cela ee .
i = EE A
MULTIPLE mode.
TEE
Frequency of burst varied,
Figure 3-11. Burst Operation.
Model 3312A
Section IV
SECTION IV
THEORY OF OPERATION
4.4, INTRODUCTION,
4-2, This section contains a complete theory of operation
for the Model 3312A Function Generator, The theory is
divided into two levels:
1. Basic Block Diagram Description
2. Functional Block Diagram Description
Detailed circuit descriptions are given for unique complex
circuits. These descriptions may be helpful when troubie-
shooting the instrument.
43. DESCRIPTION.
4-4, The 3312A combines two separate, independent func-
tion generators referred to as the main generator and the
modulation generator. The main generator output can be
controlled by the modulation generator. The major features
of the 3312A are the 0.1 Hz to 13 MHz frequency range of
the main generator and the AM, FM, sweep and tone burst
capabilities of the modulation generator. A basic block
diagram of the 3312A is shown in Figure 4-1,
4-5, BASIC BLOCK DIAGRAM DESCRIPTION.
4-6. The main. generator of the 3312A uses a voltage to
frequency conversion technique. A triangle waveform is
generated by charging and discharging a capacitor from a
constant current source. The time required to charge and
discharge the capacitor determines the period of one cycle
and, therefore, the frequency.
4-7. The triangle waveform from the Triangle Generator is
applied to the Voltage Comparator which acts as an
amplitude limiter. As the triangle waveform alternately
crosses the upper and lower switching levels of the limiter
input, a square wave is generated at the output of the
Voltage Comparator, This square wave is fed back to the
Triangle Generator where it controls the charge/discharge
cycle of the triangle output,
4-8. To obtain a sine wave, the triangle wave is shaped by a
diode network in the Sine Shaper. The diode network
serves as a non-linear load which varies the attenuation of
the input triangle according to its level.
4-9. The modulation generator can amplitude modulate,
frequency modulate, sweep, or initiate a burst from, the
main generator output. Sweep and frequency modulation
modes control the voltage output of the tuning amplifier
which determines the frequency. In amplitude modulation,
the main signal is routed through a balanced modulator
where it is mixed with the modulating signal. The percent
of modulation is controlled by the level of the modulating
signal.
4-10. The tone burst is accomplished by gating the main
generator output on and off. Multiple or single cycle
operation is determined by the duration of the low state of
the Burst Control.
4-11. The output amplifier has separate parallel paths for
the high and low frequencies. This gives it wide bandwidth
and a high slew rate to maintain good square and triangle
wave shape without compromising dc stability and low
offset. An integrated-circuit operational amplifier is used
FREQ) o
MAIN GENERATOR
VOLTAGE | Ll
DC OFFSET
MODULATION GENERATOR
[COMPARATOR
oy
TUNING TRIANGLE NJ | QUTPUT OUTPUT
AMPLIFIER> 21 GENERATOR “ >| AMPLIFIER > AT TENUATOR <
E
1:10
pi SINE У |: 100
SHAPER 111000
У BURST CONTROL.
CONTROL
I AMPLITUDE
Y
FM AND SWEEP CONTROL
MAIZ В 3954
GENERATOR
MODULATOR
Figure 4-1. Basic Block Diagram.
4-1
Section IV
for the low frequencies while the ac-coupied high-frequency
path is optimized for wide bandwidth. The two paths are
summed in the final gain stage and then buffered through
cascaded emitter-followers to the output.
4-12. The Output Attenuator provides selectable attenua-
tion for the output and an impedance match to the 50 ohm
output terminal. The attenuator reduces the amplitude of
the output signal by factors of 1, 10, 100, or 1000.
413. FUNCTIONAL BLOCK DIAGRAM DESCRIPTION.
4-14. Refer to the Functional Block diagram, Figure 7-1
for the following discussion. Detailed circuit descriptions
are referenced to figures or to the circuit diagrams of
Section VII.
4-15. The 3312A can be divided into three major sections:
1. Main Generator Section (Paragraph 4-16)
2. Output Section (Paragraph 4-29)
3. Modulation Section (Paragraph 4-33)
4-16. Main Generator Section,
4-17. Tuning Amplifier. The Tuning Amplifier is a sum-
ming amplifier which sums any current from the УСО
INPUT or the modulation source with the current present
at the input of the amplifier. The output voltage of the
amplifier is a weighted average of the input signal voltages.
The Frequency Control (Dial) varies the amount of voltage
seen at the output of the Tuning Amplifier, which
determines the frequency.
4-18. Symmetry Switch and Vernier. The front panel
Symmetry Switch operates in two modes. With the front
panel control in the CAL position (Figure 4-2) the output
of the Tuning Amplifier is connected, through two nomi-
nal 5 k§2 resistors, to the non-inverting input of U102 and
the inverting input of U103. Because the gain of U102 is
equal to that of U103, the magnitude of the voltage at the
emitters of QI01 and Q102 is equal, but due to the
inversion of U103, the emitter of Q101 is positive with
4 RUY + RI2I = RI24
4068-4014
Figure 4-2. Calibrated Symmetry.
4-2
Model 3312A
respect to ground and the emitter of Q102 is negative with
respect to ground. In the calibrated position, equal currents
flow through R122 and R123.
4-19. During variable symmetry operation (Figure 4-3), the
output of the Tuning Amplifier goes to the wiper arm of
the symmetry Vernier, and the junction of R122 and R123
is grounded. Adjusting the position of the wiper arm varies
the input resistance of U102 and U103 and. therefore, the
gain, The emitters of Q10! and Q102 will remain opposite
in polarity, but the magnitude of the voltage will differ. In
addition, different currents will flow through R122 and
R123, which means different currents in the integrating
capacitance, so that the output waveform will no longer
have a 50% duty cycle. Instead, the duty cycle may be
varied from 80% to 20% or 20% to 80%.
4-20. Positive and Negative Current Sources. The voltages
set up by the symmetry stage are transferred to the
integrating current sources through two operational ampli-
fiers. Since amplifier input impedance is near infinity, zero
current flows into the amplifier, consequently the voltage
across R119 + R121 and R124 will appear across R117 and
R126 respectively. The collector diodes of Q106 and Q107
(Figures 7-2) are current sources controlled by the emitter
current established by R117 and R126. The RANGE Hz
switches change the parallel resistances of R117 and R126
which influence the ramp time of the integrating capaci-
tance and, therefore, the frequency.
4-21. Diode Switch. The gating circuit of the Diode
Switch (Figure 7-2) allows for the charge or discharge of
the integrating capacitance. The high speed comparator,
U201 (Figure 7-3), controls the signal path through the
switch. When pin 2 of U201 is high, CR204 and CR206 are
conducting, CR203 and CR207 are reverse biased, and the
integrating capacitor charges. When pin 2 goes low, CR203
and CR207 conduct, CR204 and CR206 are reverse biased,
and the integrating capacitor discharges.
À Ril9 + Ri2i- Ri24
SHRAR- 4038
Figure 4-3. Variable Symmetry.
Model 3312A
4-22. When the diode switch is reverse biased there is a
diode capacitance which distorts the peak of the triangle
(see Figure 4-4). This distortion is removed by the level
shifting circuit of Q401 and C404. The square wave at the
collector of Q401 is passed through the ac voltage divider
of C404 and C205 and added to the triangle wave to
eliminate the “drop-off” caused by diode capacitance.
33/2 AB- 4535
| Figure 4-4, Level Shifter,
4.23. Integrating Capacitance. The integrating capacitors
are C205, C201, C202, C203, C204, and C206. Because the
current charging and discharging is constant, except for
direction, the voltage across the integrating capacitance will
be triangular. The resulting waveform is varied in frequency
by changing the current and capacitance with connections
through the RANGE Hz switches and the FREQUENCY
dial.
4.24. Buffer Amplifier. The Buffer Amplifier (Figure 7-2)
has a gain of one and consists of a FET input and a
push-pull output. The high input impedance of the FET
provides isolation, and the emitter followers Q202 and
(203, form a push-pull circuit. Diodes CR209 and CR211
are temperature compensating diodes.
4-25. Comparator. While the integrating capacitor is charg
ing, the positive-going ramp is applied to pin 4 of U201
(Figure 7-3). The positive-going ramp is compared in
magnitude, to the square wave on pin 2. Upon coincidence,
the Comparator changes state, reversing the biasing of the
gating diodes, and the integrating capacitance discharges.
Coincidence of the negative-going ramp with the square
wave now at its negative limit, switches the Comparator
back to the original state, completing one cycle of
operation,
4.26. The square wave output of U201 pin 5 is processed
by a + 5 V diode clamping network to provide the square
wave output.
4-27. Sync Generator. The Sync Generator is a simple
divider network which attenuates the output of the £5V
Section IV
clamp. The sync output is, therefore, always a square wave
in phase with the main generator (180° out of phase with
the square wave output due to output amplifier inversion)
and under the control of the Symmetry Switch.
4-28. Sine Shaper. The triangle wave from the Buffer
Amplifier (Figure 7-3) is connected through R257 to the
sine synthesizing diodes. The diodes of the sine network are
reverse biased by the resistive dividers made up of R259,
R262, R263, etc. As the triangle ramp goes positive, the
bias is overcome and the diodes in the lower half turn on
to produce a non-linear loading effect on the triangle wave.
When the ramp reaches a negative level, the upper half of
the sine shaping network begins to load the triangle wave
thus shaping the negative half of the wave. The diodes in
this section are selected for their soft turn-on characteristics
to insure a smooth sine-shaped curve.
4-29. Transistors Q216, Q217, Q218 and Q219 compen-
sate for thermal changes. This insures that the proper bias
level is maintained over a wide temperature range. In the
Model 33124, the sine shaper is followed by a low-pass LC
filter that has a sharp cutoff at 14 MHz. This filter
attenuates third harmonics substantially at generator fre-
quencies above 5 MHz, enabling the instrument to produce
sine waves with all harmonics more than 30 dB below the
fundamental up to its maximum frequency.
4-30. Output Section.
4-31. The output section consists of the Output Amplifier
and the Output Attenuator (Figure 7-4).
4-32. The amplifier system has a voltage gain of - X16 and
has been impedance matched on both sides. The ac signal is
coupled through QS01 to Q502 and Q503. To obtain a
frequency response that extends to zero, the main output is
direct coupled to US01 and then to the complementary
stage of Q504 and Q507. The dc offset is summed into pin
2 of U501 via R304. In the CAL position, R504 is opened
and no offset is summed into the output amplifier.
4-33. The output is dc coupled to the output attenuator.
The step attenuator consists of resistive attenuator sections
of 20 dB steps with an impedance of 50 ohms,
4-34. Modulation Generator.
4-35. Signal Generator. Basic to this circuit are the inte-
grator U301 and the comparator U302 (Figure 4-5). By
integrating the square wave at its input the integrator
generates a triangle wave. The level of the triangle is then
compared to the square wave and when the voltage at the
input node to the comparator equals zero IR,
(Es - E, /R; +R,) =E,] the comparator output switches
states. The square wave output from the comparator is then
inverted, clamped and fed back to the inverter to control
the generation of the triangle wave.
43
Section IV
SINE
SHAPER [0 VU
1U303
3312 АН - 5034
Figure 4-5. Signal Generator.
4-36. Amplitude Modulation. The AM modulator (Figure
7-4) is a balanced modulator which mixes the carrier signal
from the main generator with the modulation signal from
the modulation generator. The carrier frequency is applied
to pin 7 of U404 and the modulation signal is input to pin
4. Modulation amplitude control resistor R612 attenuates
the modulation signal to control the envelope of the output
signal.
4-37. Frequency Modulation and Sweep. During FM and
sweep operation the output of the modulation generator is
applied directly to the Tuning Amplifier of the main
generator. In FM operation (Figure 4-6}, R612 controls the
percent of deviation in frequency of the carrier waveform.
The change in frequency is limited to +5% of the carrier
frequency by current limiting resistor Al R426. AM three
functions of the modulation generator are available for
modulating the main generator output frequency.
4-38. When the SWP pushbutton is pressed, resistors R303
and R308 are selected. If R601 is in the CAL position, the
output of U30! is a 90:10 ramp (Figure 4-7). As R601 is
rotated clockwise, t, increases and flyback time is
increased.
4-39. The 0 Hz position of the RANGE Hz knob allows pin
5 of U303 (Figure 7-5) to go high producing a low at pin 6
of U303 and at the emitter of Q302. Q302 begins to
conduct, turning Q301 on and forming a loop with U302,
Q302, Q30! and U301. In SWP the square wave is held at
its high level and the triangle wave ramps to - 10 V then
Model 3312A
TO
RG 12 TUNING
5K AMP
A
+
"mo
=
- +
’
Ov
- 2512 - В - 40%7 -3 y N x ^^
Figure 4-7. Sweep Operation.
stops. Start frequency, for the sweep of the main generator
output, can then be selected with R162. R162 affects the
frequency of the main generator by determining the
negative voltage level at which the ramp starts. Taking the
RANGE Hz knob out of the 0 Hz position starts the
modulation generator running and, as the ramp voltage
approaches zero volts, the output frequency of the main
generator approaches the frequency of the dial setting,
4-40. Burst. At any setting other than FREE RUN, the
tone burst gate is operable. The start/stop phase of the tone .
burst is determined by R615 (Figure 4-8) and the transistor
array U403. The signal always stops in the same phase as it
started.
4-41. When TRIGGER PHASE is in FREE RUN the line
from the Burst Control is open and U402A pin 2 is pulled
low by the negative supply causing a high at the output of
U402A. As a result Q402 and U403(c) turn on and U403(a)
and (b) turn off. With U403(a} off, CR408 is reverse biased
and no charge is drawn off the integrating capacitor
allowing the main generator to free run.
4-42. In TRIGGER PHASE a low from the burst control
appears on U402A pin 2 forcing the output of U402A high
and starting the burst. When the burst control line goes high
again followed by a positive transition of the square wave
(at U402A pin 1) the output of U402A goes low. Q402
now turns off allowing TRIGGER PHASE POT, R615, to
RECH R304
1Jle
ee TE o
REGIE TUNING
SK AMP
— SINE
SHAPER
2312 -8-4036
Le
Figure 4-6. FM Operation.
4-4
Model 33124
determine the voltage at the base of U4203f(e) and in turn at
the base of U403(c}. When the voltage from the main
generator (via the BUFFER AMPLIFIER) appearing at the
base of U403(b) equals that at the base of U403(c), both
U403(a) and (b) turn on and U403(c) turns off. (R408
forward biases and clamps the integrator output to the
voltage at the base of U403(c) (which was originally
determined by TRIGGER PHASE POT, Rio). With the
integrator output held at that level the comparator does not
switch the current sources resulting in a de level at the
square wave output. When the burst control goes low again
the voltage on the integrating capacitor will determine the
phase at which the burst restarts. Thus, R615 controls the
start/stop phase.
— 4-43. Multiple Cycie Burst Mode (Figure 7-3). The main
generator is gated off when the burst logic sees a positive
square wave transition after the burst input to U402 pin 2
goes high, If the main square wave is already high, the main
generator will not be gated off until the main square wave
first goes low then returns high, The waveforms in Figure
4-9 should serve to clarify the operation of the burst logic.
4-44. Single Cycle Burst Mode. In single cycle operation
(Figure 7-3), U402A pin 2 is driven from U40l, a
monostable one-shot multivibrator. After being inverted the
output of U402 is normally high. Triggering of U401 causes
U402A pin 2 to go low for 40 nanoseconds, after which it
returns to its quiescent high state. This 40 nanosecond low
pulse is sufficient to start the main generator. Since pin 2
Section IV
FROM BURST CONTROL
o FREE RUN
TRIGGER PHASE
TV
MAIN
SQUARE
WAVE
FROM CR408 r
NTEGRATOR
TP3 |
|
—17V AAA
{
|
|
|
|
FROM ;
BUFFER :
AMP
REIS
{
|
L.
7
TRIGGER
147 —B- 4038 PHASE POT
Figure 4-8. U403 Burst Amplifier Array,
almost immediately returns to a high state, the main
generator runs until the triangle returns to its start/stop
phase position, at which time the generator stops, comple-
ting one cycle of operation.
MAIN SQUARE
TP 4
MAIN ZA
BURST CONTROL
|
AIR ee \WAVAVAVAV
E
| |
UUL
NV
[40212 |
|
|
[
|
INVERTED ONE + fe
SHOT OUTPUT |
U4C2(2)
|
|
|
TAI —ñÑ,
SINGLE CYCLE
TRIGGER MODE |
|
ara gered oe, re
|
|
|
|
|
|
| | |
|
|
|
|
3H24-B-4305
Figure 4-9. Burst Time Relation Waveforms.
">