pass filter in the output for removing subcarri- 
er ripple from the recovered data signa]. One 
more discriminator is used to detect variations 
in the frequency of the reference signal. The 
output of this unit is applied to the other 
discriminators in such a way that it corrects 
the effects of tape speed variation. The in- 
spect function may be provided by connecting a 
multi-channel recording galvanometer to the 
outputs of the discriminators. 
The function of the Programmer-Digitizer 
is to sample analogue voltages and convert them 
into a binary digital format suitable for 
direct entry into the Recomp II computer. 
This may be done simultaneously with, or 
independently from the graphic presentation. 
The Programmer-Digitizer has 12 input 
connections on a patch panel to receive up to 
12 analog voltages. The number of input con- 
nections used in a given case is called the 
GROUP SIZE and may be any number from 1 to 12. 
A dial marked GROUP SIZE SELECTOR is set to 
correspond with the number of input connections 
in use. 
An internal switching device scans all 
of the active input voltages in sequence and 
transmits the voltage to an analog-digital 
converter. The frequency with which the 
switching device scans the entire GROUP of 
voltages is called the GROUP SAMPLING RATE 
and is adjustable by dial settings from 1 to 
100 times per second. Since the patch panel 
permits plugging the same voltage into any or 
all twelve inputs it is possible to sample 
a single voltage 1200 times per second, two 
voltages 600 times per second, 12 voltages 
100 times per second and so on. It should be 
noted, however, that the sampling speed of 
the Programmer-Digitizer may exceed the abil- 
ity of the computer to receive digitized in- 
formation. If need arises, and as opportunity 
is presented, the computer capabilities will 
be suitably improved. 
Since the computer memory has a finite 
capacity it is necessary to provide a means 
of limiting the number of samples which will 
be stored. A panel control marked TOTAL is 
set to the total number of samples per chan- 
nel desired. The computer capacity is in 
excess of 12,000 DATA WORDS so that for a 
GROUP SIZE of 12 the maximum permissible 
TOTAL setting would be something over 1000. 
For a GROUP SIZE of 2 the TOTAL setting could 
be over 6000 and so on. 
Manual controls are provided to allow 
the programmer to be advanced manually through 
the samplirg sequence, during calibration and 
test procedures, and to permit sampling rates 
to be controlled by accessory apparatus. 
59 
A visual binary display of the buffer 
contents is provided on the panel. 
The sampling sequence is as follows: 
1) Upon receipt of a signal from the 
computer the analog tape playback is energized. 
2) The channel 
to input number 1 and 
that input. In order to achieve accuracy 
when sampling rapidly varying data the time 
duration of the sample, called the aperture 
time, is limited to 1 microsecond. 
selector switch steps 
samples the voltage at 
3) The sampled voltage is converted into 
a 10 bit binary number and read directly into 
the computer. The actual timing sequence of 
this operation depends upon the input capabil- 
ity of tue computer. 
4) The channel selector switch is then 
stepped to input number 2 and the above opera- 
tion repeated. Stepping continues through 
successive inputs until the number of inputs 
specified by the GROUP SIZE selector have been 
sampled. The channel selector switch is then 
returned to its off position. At this point 
a timing device is actuated causing the chan- 
nel selector to wait an interval of time before 
recycling through the various inputs. The 
time delay is determined by the setting of 
the GROUP SAMPLE RATE dials. 
5) After completion of each group 
sampling the programmer advances the group 
counter by one count and compares the 
‘counter with the setting of the TOTAL dials. 
When the two numbers agree the programmer 
generates a termination sequence to the com- 
puter which stops data filling and may cause 
the computer to start executing an internal 
program. 
The present computer used with the 
ADDReSOR is an Autonetics Recomp II which 
requires 7.5 ms to enter and store each 
DATA WORD. Thus a total of 90 ms is required 
to scan all 12 channels, or in other words 
a phase lag of nearly 180° would occur 
between 10 cps data on channel 1 and channel 
12. Furthermore, this relatively slow input 
rate limits the system to 1l samples per 
second per channel when using all 12 channels, 
22 samples per second per channel for 6 
channels and so on. This restriction means 
that no more than 5 cps intelligence frequency 
can be recovered when using all twelve channels, 
10 cps intelligence frequency can be recovered 
when using 6 channels, etc. Present plans call 
for incorporating a faster computer into the 
data processing system in the near future so 
that these restrictions will be removed. 
