CONECTION MACHIG UNT

CONECTION MACHIG UNT
United States Patent [191
[11]
4,295,154
Hata et a1.
[45]
Oct. 13, 1981
[56]
[54] DIGITAL VIDEO AND AUDIO FILE SYSTEM
References Cited
U.S. PATENT DOCUMENTS
[75] Inventors: Hidetoh Hata, Yokohama; Katsumi
3,921,209 11/1975
4,003,079 l/l977
4,150,397 4/1979
4,175,270 ll/l979
Haji, Narashino; Kazushige Sako,
Tokyo; Yoji Shibata, Yokohama;
Masahiko Achiha, Iruma, all of Japan
Primary Examiner—Alan Faber
Attorney, Agent, or Firm-Craig and Antonelli
[73] Assignees: Nippon Telegraph, Telephone Public
Corp.; Hitachi, Ltd., both of Tokyo,
[5 7]
Japan
ABSTRACT
A digital video and audio ?le system is provided for use
in systems such as a center-to-end video communication
system. In the ?le system, video information, such as a
[21] Appl. No.: 63,467
[22] Filed:
Yoshino .............................. .. 360/32
Woo ........ ..
358/4
Russell .... ..
360/9
Zenze?lis ............................ .. 360/19
color television video signal, is digitized in such a man
ner that it is separated into a luminance (Y) signal and a
Aug. 3, 1979
carrier chrominance (C) signal and these separated
components are processed by the code differential
[30]
method and the variable length encoding method. The
digital signal thus digitized is recorded in a digital re
corder. On the other hand, audio information is digi
tized by the AD-PCM encoding method and recorded
Foreign Application Priority Data
Aug. 4, 1978 [JP]
Aug. 4, 1978 [JP]
Japan ................................ .. 53-94586
Japan ................................ .. 53-94588
[51]
Int. (11.3 ............................................. .. H04N 5/76
[52]
us. c1. .... ..
in the same recorder. In encoding the video and the
audio information, a part of hardware is used in com
mon for both the signals, thus saving the hardware of
358/4; 360/33;
the ?le system.
360/32; 360/9; 360/19; 3523/127
[58]
Field of Search ....................... .. 360/32, 9, 33, 19;
12 Claims, 12 Drawing Figures
358/127, 4, 31, 13, 133, 135, 143
II
MIUDFI LM
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RAN DGIA
ACCESS
MOTION
ICTURE VIDEO
FILE UNIT
I
$1AUDIO
MULTI-FRHIJB‘ICY
SIGNAL RECEIVER
US. Patent
Oct. 13, 1981
Sheet 2 of 8
4,295,154
U.S. Patent
OCt. 13,1981
Sheet5 of8
4,295,154 I
F I G. 8
"76 FIELD
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U.S. PatGnt
0a. 13, 1981
F| (3_ 9a
Sheet 6 of 8
4,295,154
MATERIAL REGISTERING SEQUENCE
START
INPUT
oPERATIoN
BY AN
OPERATOR
TURN A KEY- BOARD
I SWITCH To A LOCAL MoDE
i
TURN ON A REGISTER
SWITCH FOR A VIDEO
SYSTEM
'
_
SYSTEM
ADJUST Tv CAMERA
(VTR) MATERIAL
ADJUST MIcRoPHoNE/TAPE
REcoRDER MATERIAL
SET A PARAMETER
(SAMPLING
f)
u REGISTER A Q SIGNAL
'
MANUALLY REGISTER
(6,5 BITS /8 BITS)
I
BEING
START THE QSIGNAL“
PUSH A CODE START
REGISTERE
Bum“
PUSHO? coDE START
sToP THE QSIGNAL
BU"
~
R/EDGégTERATION INTO A I
l
I
TURN DN A REGISTRATION
SwITcH FOR AN AUDIO
REG-IS RA ION
BUFFER ENDS
PUSH A CODE STOP
-
BUTTON
BEING
I
--———-—————-—
1
REGISTRATION INTO A
I
AUDIO REGISTRATION
I
BUFFER ENDS
I
TURN ON AN'AUDIO
READ SWITCH "IO
RENDER IT IN A CODE
START
PICTURE AUTOMATICALLY
MONITOR A SOUND FROM
ASPEARS ON A MONITOR
A SPEAKER
0K?
YES
REGISTERED
U.S. Patent
Oct. 13, 1981
Sheet 8 of8
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4,295,154
2
DIGITAL VIDEO AND AUDIO FILE SYSTEM
?led in a digital recorder, two independent ?le systems
are used for the respective video and audio signals.
With such a construction, although most of the hard
The present invention relates to a ?le system for ?ling
the audio and/or video information which is used in a
wares are used in common for the two signal ?lings,
those are separately and independently used, so that the
center or a subcenter of a multiplex information service
system cost is expensive and uneconomical. Generally,
the audio and video signals are processed in pair. Such
signal processing is dif?cult when the conventional ?le
system with two different ?le systems is used.
Accordingly, an object of the invention is to provide
system of the above-mentioned type which is a kind of
television-telephone combined system using nationwide
communication networks. More speci?cally, the pres
ent invention relates to a digital video and/or audio ?le ,. . 0
system in which the video information, mainly the tele
vision picture, and the audio information are digitized
and, through the digitization, most of the hardwares are
a digital video and audio ?le system which is low in cost
and easy to operate.
used in common for both types of information, and the
video and audio ?le system which is low in cost and
digitized ones are stored in a digital memory or re
allows a high speed read-out operation.
corder.
To cope with a recent tendency of information that
One of the major features of the invention is that a
digital signal capacity of one frame of a TV picture is i
the information becomes complicated and highly ad
vanced, many countries have made intensive efforts for
developing a multiplex information service system for
to 1/9 of that of the conventional system and the cost of
a still picture ?le system is reduced % to l/6 compared
to the conventional one, and the data access speed is
improved two to six times over that of the conventional
servicing pictures, data and the like by using wide-band,
large channel-capacity communication networks, and
some countries have put such systems into practice.
One of the approaches to realize the multiplex infor
Another object of the invention is to provide a digital
?le system.
Another features of the invention is that a code for
mat is used which is usable in common for the video and
mation service system is to use multi-purposely the 25 audio signals thereby to allow all the hardware between
a digital buffer memory and a digital recorder to be used
media. As for the use of the broadcasting system, a
for both the signal systems.
broadcasting and the telephone systems which are basic
character multiplex broadcasting system is already in
practice in England, and this has triggered other
countries to start practice-purpose experiments of audio
and character multiplex broadcasting systems. As for
the use of the telephone network, the Post Of?ce in
Other objects, features and advantages of the present
invention will become apparent from the following
detailed description of preferred embodiment thereof
taken in conjunction with the accompanying drawings,
England is now performing an experiment of an infor
mation service system (PRESSTEL) for the purpose of
in which:
FIG. 1 shows a system block diagram of a video
communication system to which a digital video and
practical use, and this system is enjoying favorable eval
audio ?le system according to the invention is applied;
uation.
Attempts heretofore made to multi-purposely use the
digital video ?le system according to the invention;
broadcasting and the telephone systems may be roughly
categorized into: (1) Effective utilization of communi
cation networks already used; (2) Practical application
FIG. 2 shows a block diagram of an embodiment of a
FIG. 3 shows in block form the details of a digital
signal processing unit and a high ef?ciency encode
40 circuit which are used in the system shown in FIG. 2;
of the systems to local; small-scale information service
systems for the public; and (3) Prevalence of informa
tion service systems used exclusively for private pur
FIG. 4 shows in block form the detail of a code differ
ential encoder circuit used in the system in FIG. 2;
FIG. 5 is a table comparatively tabulating the record
poses. In the center-to-end type video and audio com
ing or memory capacities per frame between the ?le
munication system thus practiced in use, video ?les 45 system of the invention and the conventional one;
which may be installed at the center and retrieved are
FIG. 6 shows a table comparatively tabulating access
digital recording mediums such as micro?lms, holo
times of a digital recorder when the ?le system accord
grams, video discs, video recorders (VTR), and digital
ing to the invention and the conventional one are used;
recording mediums such as memory units with very
FIG. 7 shows a block diagram of another embodi
large capacity. Of those analog recording mediums, the
ment of a digital ?le system according to the invention;
micro?lms including large capacity micro?lms and
FIG. 8 shows the formats of a digital video signal
super-capacity micro?lms, holograms and video discs
code and a digital audio signal code;
are impossible in rewriting video information thereinto.
On the other hand, the recording media of the digital
system allows the rewriting of the video information. In
the case of digital magnetic discs, for example, video
recording of material into the digital ?le system accord
ing to the invention;
signals as TV signals are recorded in such a manner that
they are passed through an A/ D converting circuit and
are pulse code modulated. The PCMed signals are then
recorded in a digital recording unit. In the recording
FIGS. 9a and 9b show a flow chart for illustrating the
FIG. 10 shows a set of timing diagrams for illustrat
ing an operation sequence of the ?le system according
to the invention; and
FIG. 11 shows a table illustrating economical features
of the ?le system of the invention, while comparing
method, however, since recording or memory capacity
them to the conventional one.
of the TV picture ranges from 300 KB to 500 KB, a unit
Reference is ?rst made to FIG. 1 illustrating in block
form a video and audio response service system of the
center-to-end system equipped with a digital video or
video and audio ?le system according to the invention.
As shown, the video and audio response service system
is generally comprised of a center 1 and a terminal set 2.
The center 1 is comprised of a central processing unit
for recording the picture in the form of digital signals is
very expensive. Further, the access time from the digi
tal recording unit is long, e.g. 0.4 to 0.7 see, so that it
takes a long time for read-out operation‘.
In a conventional digital ?le system of the type in
which the audio and the video signals are digitized and
3
4,295,154
(CPU) 3, a monitor control unit 4, a data typewriter 5,
a card reader 6, a magnetic disc pack 7, a magnetic tape
8, a line printer 9, a connection matching unit 10, a
micro?che search unit 12, a picture/character genera
tor 13, a digital video ?le unit 14, a random access mo
tion picture video ?le unit 15, an audio response unit 16,
a PARCOR type audio per picture ?lm unit 17, a sche
duled-time motion picture video ?le unit 18, a video
distributing/coupling unit 19, a frame memory 20, a
video changeover unit 21, an audio buffer memory 22,
an audio changeover unit 23, a video output unit 24, a
character generator 240, microcomputer 25, a multi-fre
quency signal receiver 26, an audio output unit 27, an
exchanger 28, and terminal units 29a and 29b.
The terminal set 2 is comprised of converters 30a and
3%, television receivers 31a and 31b, push-phones or
simple key-boards 32a and 32b. The terminal set 2 is
4
are passed through comb type ?lters 145 and 146 in
order to remove cross color and dot disturbances and to
improve the coding efficiency. Then, those ?ltered-out
signals are applied to the Y signal D-PCM encoder
circuit 147 of 3 to 7 bits and the C signal D-PCM en
coder circuit 148 of the same number of bits for the
predictive encoding. As shown in FIG. 3, the circuit
blocks 144 to 148 cooperate to form a high ef?ciency
encoder circuit for digitizing the TV analog signal.
Although the Y and C separation type D-PCM system
is employed in the embodiment, any other suitable sys
tem may also be used. After that, the digitized TV sig
nal is temporarily stored in the digital buffer memory
149. The buffer memory 149 is used to change the speed
of an input signal and to convert an interlaced received
signal into a non-interlaced signal. Then, the digital TV
output signal 158 enters the code differential encoder
interconnected with the center 1, through transmission
circuit 153 where it is subtracted from a signal D-PCM
lines 33a and 33b. In the ?gure, reference numerals 34a
signal preceding by one horizontal scanning period to a
and 34b designate wide-band repeat ampli?ers 34a and 20 marked sampling point of the D-PCM coded signal.
3411.
The output signal from the code differential encoder
In operation, a handset of the push-phone 32a of the
circuit 153 is inputted to the variable length encoder
terminal set 2 is removed from the hook and then the
circuit 154. Of the output digital signals from the vari
center 1 is dialed. Upon a response from the center 1,
able length encoder circuit 154, short codes are assigned
the desired video and audio information is requested by 25 to the signals which appear frequently while long codes
using the push-phone. The center 1 responds to the
are assigned to the signals which seldom appear, and a
request from the terminal set so that the related respec
variable length code signal is formed by the variable
tive units in the center 1 systematically operate. As a
length encoder. The variable length code signal is then
result, a video signal (base band) and an audio signal are
under control of the signal control unit 142 and is stored
transmitted to the terminal set 2, through the video and
into the digital recorder 143.
the audio output units 24 and 27, the exchanger 28, and
In reading out the TV signal, an inverse control oper
the terminal units 290 and 29b, and further the transmis
ation is performed. Speci?cally, as indicated by an ar
sion lines 33a and 33b and the wide band repeat ampli?
row, the recorded information from the digital recorder
ers 34a and 34b. Those signals received by the terminal
143 is applied through the signal control unit 141 to the
sets are converted by converters 30a and 30b into the 35 variable length encoder circuit 154 and then is applied
NTSC system (or PAL system) and then are repro
to the code differential encoder circuit 153 where it is
duced by ordinary home-use television sets. In this man
restored to its original state. The restored signal is ap
ner, the desired video signal and the audio signal are
plied to the Y signal D-PCM decoder circuit 150 and
obtained.
the C signal D-PCM decoder circuit 151, through the
Turning now to FIGS. 2 and 3, there are shown 40 digital buffer memory 149. The decoded signals 159a
circuit constructions of a digital video ?le system 14
and 1591) decoded by the decoder circuits 150 and 151
according to the invention which may be adapted for
are composed by the composing circuit 152. Finally, the
the above-mentioned system. The circuit constructions
desired original NTSC signal is obtained from the out
shown are for recording a TV signal. In the ?gures,
put terminal 160.
reference numeral 141 designates a TV signal process 45
The detail of the code differential encode circuit 153
ing unit; numeral 142 a signal control unit including a
used in the digital video and audio ?le system according
digital recorder input/output controller 1420, a com
to the invention is shown in FIG. 4. In the ?gure, refer
mon controller 142b and a BCT counter 1420; 143 a
ence numeral 153a designates a horizontal scanning
digital recorder or memory unit with a large capacity.
delay circuit and numeral 153!) a subtractor circuit. A
The TV signal processing unit 141 is comprised of a Y 50 digital TV signal 158 read out from the digital buffer
and C signal separator 144 for separating a luminance
memory 149 is subtracted from a signal delayed by one
(Y) signal and a chrominance (C) signal, a comb type
horizontal scanning time, i.e. a D-PCM signal before
?lter 145 for the Y signal, another comb type ?lter 146
one horizontal scanning time, in the horizontal scanning
for the C signal, a D-PCM encoder circuit 147 for the Y
period delay circuit 153a. The subtracted one is input
signal including a D-PCM encoder 147a for the Y signal
ted to the variable encoder circuit 15A where it is pro
and a D-PCM decoder 147]), a D-PCM encoder circuit
148 for the C signal including a Y digital buffer memory
cessed by the variable length encoding method.
An experiment conducted by the inventors showed
the following results. In the experiment, by using a
predictive encoder circuit, the TV signal is separated
149a and a C digital buffer memory 14%, a D-PCM
decoder circuit 150 for the Y signal, a D-PCM decoder
circuit 151 for the C signal, a composing circuit 152 for 60 into the Y and C signals. These separated signals are
composing the Y and the C signals, a code differential
subjected to D-PCM encoding of5 bits with sampling at
circuit 153 provided at the output portion of the digital
buffer memory 149, and a variable length encoder cir
three times subcarrier frequency. The picture quality is
kept at 4.5 or more with respect to the ?ve-grade evalu
cuit 154.
ation. With respect to the high efficiency coding of the
In operation, an NTSC signal as a TV signal is ap 65 main, when recording is made of only the video signal
plied to an input terminal 155. Upon receipt of the TV
signal, the separator 144 separates the TV signal into a
Y signal 156 and a C signal 157. The separated signals
portion except the code differential, the variable length
recording and the synchronizing signal sections, the
recording capacity of one picture is l to l/9 of that of
5
4,295,154
6
the conventional one, as shown in FIG. 5. The memory
capacity of one picture thus results in i to 1/9 of the
into the same signal format as the video signal. The
maximum length of a ‘sentence of audio signal recorded
conventional one. Therefore, the data transfer time
from the digital memory unit is substantially reduced.
When the digital recording system such as the computer
disc IBM3330-l l‘ is used, the searching time is reduced
buffer memory 166 and is approximately 20 sec. The
is determined ‘in accordance with the capacity of the
audio signal is applied to the audio encoding circuit 174
where it is subjected .to AD-PCM, or AM or linear
PCM to be digitized is loaded into the buffer memory
to be % to US, as shown in FIG. 6.
FIG. 7 shows another embodiment of the digital
video and audio ?le system according to the invention.
166. The digitized audio signal is transferred to the
buffer memory where its transfer speed is changed to
that of video signal. The speed-changed digital audio
signal is transferred from the buffer memory to the
interface circuit 168, through the by-pass circuit 177.
Leaving the interface circuit 168, the audio signal is
written into the large-capacity digital recorder 163. The
code format of the digital audio signal includes a param
A feature of the ?le system resides in that a code format
employed for the audio digital signal is the same as that
of the video digital signal, and the hardware between
the digital buffer memory and the digital memory unit is
used in common for both the video and the audio digital
signals. The video signal and the audio signal are ap
plied to a video and, audio processor 161 where these
eter ?eld 172, a frame synchronization ?eld 173, a digi
are digitized and encoded in the form of proper coding
tal
audio signal ?eld 179, and a line synchronization
formats. The coded signal is recorded into a digital
field 176, as shown in FIG. 8.
recorder 163 under control of a signal control unit 162.
In reading out data, the operation is performed at the 20 As described above, the digital audio signal is treated
in exactly the same way as the linear PCM signal of the
respective portions in an inverse manner.
digital
picture signal is treated. Accordingly, little addi
The operation of the video and audio processing unit
tional hardware for the audio ?le is needed, except the
161 will be explained below. For recording a picture, a
audio encoder circuit 174. As a result, the video ?le
video input signal 164 such as a TV signal is subjected
to PCM. In this case, only the ?rst sampled valueimme 25 system may be adapted for the audio ?le system, with
diately after the horizontal blanking period is termi
nated, and several sampled values of the color burst
signal are PCMed. Alternately, the remaining part of
being little changed.
167 with the same constructions as those of 153 and 154
the table shown in FIG. 11. Further, the saved or econ
omized portions as a result of the use of the common
Turning now to FIGS. 90 and 9b, there is shown a
?ow chart for illustrating a procedure for recording
material, or the audio and the video information, into
the video input signal is D-PCMed. In that case, the
PCM or the D-PCM operation is performed by a video 30 the digital video and audio ?le system mentioned above.
In the ?ow chart, blocks with thick lines indicate input
encoder circuit 165 with the same constructions as those
operations by an operator. FIG. 10 shows an operation
of 144 to 148 shown in FIG. 2. Then, one frame of the
sequence of the ?le system at that time.
TV signal is temporarily stored in a buffer memory 166.
From the foregoing description, it is seen that the
After that, data is read out at a proper speed from the
buffer memory 166 and the read-out data is processed 35 circuit portion handling the digital signal is quite com
mon for the video and the audio signals. For this, the ?le
by the code differential method and the variable length
system of the invention is very economical, as seen from
encoding method in a digital signal processing circuit
shown in FIG. 3. The thus processed signal is outputted
through an interface circuit 168 and then is recorded in
circuitry for the video and the audio signal processings,
the digital recorder through the signal control system
are as shown in FIG. 11. In the tabulation of FIG. 11,
162. For the PCM signal, the coding processing is not
necessary, and the PCM signal is directly applied from
the large capacity digital ?le or recorder is not consid
ered because it changes on the basis of the system con~
struction, for example, the number of pictures to be
the buffer memory 166 to the interface circuit 168,
through the by-pass switch 169. Succeedingly, the sig
45 ?led.
What is claimed is:
nal inputting operation is made in a similar manner. The
format of the video signal code as shown in FIG. 8, is
comprised of a parameter ?eld 172, a frame synchroniz
ing ?eld 173, a linear PCM signal ?eld 174, a high ef?
1. A digital video ?le system comprising:
a high efficiency encoder circuit for converting an ana
log TV signal into a digital TV signal;
a buffer memory circuit for temporarily storing the
ciency encoded signal ?eld 175 and a line synchronizing
?eld 176. In the format, the parameter ?eld 172 includes
digital TV signal;
a digital signal processing circuit coupled to the output
codes representing a discrimination of the video and the
of the buffer memory for reducing in the digital form
audio, the number of data in one frame, and sampling.
a redundancy of the digital TV signal in the ampli
The line synchronization ?eld 176 includes codes repre
senting a discrimination of the luminance signal and the 55 tude direction in a code differential manner;
color signal or an interval of the synchronizing signal.
a digital variable length encoding circuit coupled to the
Incidentally, during the interval, the buffer memory is
signal. Accordingly, the buffer memory 166 is used as a
speech changing memory and a code conversion mem
output of the digital signal processing circuit for gen
erating a digital variable length output coded TV
signal from the output signal of the digital signal
processing circuit; and
a large-capacity digital recorder coupled to the digital
variable length encoding circuit for recording the
digital variable length output coded TV signals.
2. A digital video ?le system according to claim 1, in
which said high ef?ciency encoding circuit includes a
separating circuit for separating the analog TV signal
into a luminance (Y) signal and a chrominance (C) sig
ory for converting the signal format of the audio signal
nal, a ?rst comb type ?lter for the Y signal, a second
refreshed.
In reading out data, the operation is made in a manner
inverse to that when the video input signal is recorded, 60
as mentioned above.
Next, the input and output operations of the audio
input signal 180 will be described. There is a difference
of approximately 103 times between the sampling fre
quencies of the audio input signal and the video input
65
7
4,295,154
8
comb type ?lter for the C signal, a Y signal encoding
circuit, and a C signal encoding circuit.
3. A digital video ?le system according to claim 1 or
2, in which said encoding circuits for the Y and C sig
?lter for the C signal, D-PCM encoder for the Y signal
and a D-PCM decoder for the C signal.
7. A digital video and audio ?le system according to
claim 5, in which said video signal processing circuit
includes a digital variable length encoding circuit and a
code differential encoding circuit.
8. A digital video and audio ?le system according to
claim 5, in which said audio signal processing circuit is
nals each include a D-PCM encoder.
4. A digital video ?le system according to claim 1, in
which said digital signal processing circuit includes a
code differential encoding circuit.
5. A digital video and audio ?le system comprising:
a circuit for digitizing an audio signal by using an AD
PCM, or AM or linear PCM method.
a high ef?ciency encoding circuit for converting an
analog TV signal into a digital TV signal;
9. A digital video ?le system according to claim 1 or
2, further comprising:
an encoding circuit for converting an audio signal with
a variable length code demodulator and a code differen
a ?xed time length into a digital audio signal;
tial demodulator coupled between the digital re
a buffer memory circuit for temporarily storing the two
kinds of digital signals derived from both said encod 15 corder and the buffer memory for demodulating re
corded digital variable length coded TV signals and
storing the demodulated digital TV signals in said
ing circuits;
a digital signal processing circuit coupled to the output
of the buffer memory for reducing in the digital form
a redundancy of the digital TV signal in the ampli
buffer memory;
a decoder circuit coupled to the buffer memory for
decoding the demodulated digital TV signals into
analog TV signals; and
tude direction in a code differential manner;
a large capacity digital recorder coupled to said digital
processing circuit output for recording the digital TV
and digital audio signals;
a composing circuit coupled to the output of the de
coder circuit for composing the decoded analog TV
a by-pass circuit coupled between said buffer memory 25
and said recorder to allow bypassing of said digital
signal processing circuit for the digital audio signals
5, wherein the buffer memory circuit includes means for
converting the signal format of the digital audio signal
30 into the same signal format as the digital TV signal.
12. A digital video ?le system according to claim 1 or
ing circuit and said buffer memory.
6. A digital video and audio ?le system according to
claim 5, in which said high ef?ciency encoding circuit
includes a separator for separating the analog TV signal
into a luminance (Y) signal and a chrominance (C) sig
10. A digital video ?le system according to claim 9,
wherein the decoder circuit is a D-PCM decoder.
11. A digital and audio ?le system according to claim
stored in said buffer memory which do not need pro
cessing in said digital signal processing circuit; and
a signal control unit for controlling signals transferring
between said digital recorder and said digital process
signals.
35
7, wherein the digital variable length encoding circuit
encodes the output signal of the digital signal processing
circuit by assigning short codes to signals which appear
frequently and long codes to signals which appear infre
quently.
nal, a comb type ?lter for the Y signal, a comb type
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