Digital Section. Shure SLX 2

The SLX SLX2 is a frequency-agile UHF handheld transmitter. It operates for a minimum of 8 hours using two "AA" alkaline batteries. It is designed for use with SM58, BETA 58, SM86, and BETA 87A&C microphone heads, and features an internal antenna for optimum range and reliability. This product is intended for use in entry-level presentation, installed, and performance markets.

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DIGITAL SECTION

ACCESSING DIFFERENT MODES

ATE MODE

If TP_PB0 is held to TP_EGND, or logic level 0, at startup, the microcontroller will enter ATE

Mode. To ensure proper operation, TP_PA0 and TP_PA1 should be held to TP_EGND at startup.

In ATE Mode, each band has a three test frequencies that are controlled by the logic levels at test points TP_PA0 and TP_PA1.

Test Frequencies (MHz)

SLX2

Low

Center

High

H5

518.400

529.500

541.800

J3

572.400

583.500

595.800

Frequency

Low

Center

High

JB

806.125

807.500

809.750

L4

638.400

649.500

661.800

TP_PA0 TP_PA1

P4

702.100

714.000

725.900

Q4

740.125

746.325

751.875

R5

800.525

810.275

819.800

S6

838.100

851.300

864.800

RF BAND RESISTORS

Two resistors (R

and R

) are responsible to start the microcontroller in a RF band. They determine the voltage at test point TP_RFBAND.

This table shows R

's and R

's reference designators and how the voltages at the test points reflect the operating RF band.

SLX Reference Designators

SLX2

R

R319

R

R320

This figure depicts the voltage divider feeding the microprocessor analog to digital converter.

25A1090 (Rev.3)

This table shows the variant resistor values and resulting voltages at TP_RFBAND for each band.

RF BAND

1.00k

2.99k

4.99k

7.50k

12.10k

18.2k

30.1k

49.9k

TP_RFBAND(+/- 0.10V)

0.30V

0.76V

1.10V

1.41V

1.81V

2.13V

2.48V

2.75V

Note: Voltages are calculated with a 3.30V (+/- 0.10V) reference from the power

supplies. If power section supports less than 3.30V, thresholds need to be adjusted.

µC DECISIONS BASED ON ANALOG VOLTAGES

BATTERY_A2D

Measured @ 3V block battery clips

Continuous Operation Battery Thresholds

RF Level

- dBC

Display Logic

Voltage (V)

2.25

- dBC < 2.25

- dBC

-8 dBC

2.14

2.05

Note: There is a dead battery lock voltage set at 2.30 Volts. If the transmitter is powered on with a voltage of less than 2.30 Volts, the system will lock, forcing the user to either recharge or replace the batteries. During the dead battery lock out, the battery gauge is empty and the red led flashes.

25A1090 (Rev.3)