Specifications
19A705178
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ROCKWELL MODEM TEST
SPECIFICATION/PURCHASE PART DRAWING
CONT ON SHEET SH NO. FIRST MADE FOR
F. C. F. O.
MADE BY
R. Sager
APPROVALS
DCB
M. R. P. D.
DIV OR DEPT.
19A705178
ISSUED
Nov. 19, 1986
11-18-86
LYNCHBURG
LOCATION
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REVISIONS
L30
PRINTS TO
INTRODUCTION
The R96FAX, R96DP, R48DP, AND R96FT modems
include integrated analog devices using switched capacitor
filters to perform the functions of receiver input bandpass
filtering, transmitter output lowpass filtering, and
compromise equalization. Differences in performance
result form half-duplex (HDX) or full-duplex (FDX)
versions of the integrated analog device.
R96 FILTERS
The following tables illustrate the response of the receiver
input bandpass and transmitter output low pass filters
without compromise equalization.
A. Receiver Input Bandpass Filter
Parameter Value
Test signal range 0 dBm to -45 dBm
Passband 400 Hz - 3000 Hz
Passband ripple 0.5 dB max.
Loss below 60 Hz 40 dB min.
Loss above 6000 Hz 40 dB min.
Passband gain
0.0 dB
±
1.0 dB
Delay distortion 400 Hz - 1800 Hz Less than 1000 usec
Delay distortion 1800 Hz -
3000 Hz
Less than 150 usec
B. Transmitter Output Lowpass Filter
Parameter Value
Test signal 0 dBm to -16 dBm
Passband 400 Hz - 3000 Hz
Passband Gain
-1 dB
±
1 dB
Passband ripple 0.5 dB max.
Loss at 3600 Hz 5.5 dB min.
Loss at 7800 Hz 32 dB min.
Loss at 11400 Hz 33.5 dB min.
Loss at 12000 Hz 41 dB min.
Loss above 17400 Hz 45 dB min.
Delay distortion 400 Hz - 3000 Hz Less than 300 usec
The following tables illustrate the change in filter response
caused by enabling each of the compromise equalizers
independently.
A. Receiver
1. Link Amplitude Equalizer HDX and FDX.
Frequency Gain dB Relative to 1700 Hz
Hz US Long Japanese 3 Link
1000 -0.27 -0.13
1400 -0.16 -0.08
2000 +0.33 +0.16
2400 +1.54 +0.73
2800 +5.98 +2.61
3000 +8.65 +3.43
2. Link Delay Equalizer FDX Only.
Frequency Delay Microseconds Relative to 1700 Hz
Hz US Long Japanese 3 Link
800 -498.1 -653.1
1200 -188.3 -398.5
1600 -15.1 -30.0
1700 +0.0 +0.0
2000 -39.8 +11.7
2400 -423.1 -117.1
2800 -672.4 -546.3
3. Cable amplitude HDX and FDX.
a. Code 1
Frequency Gain dB Relative to 1700 Hz
Hz HDX FDX
700 -0.99 -0.94
1500 -0.20 -0.24
2000 +0.15 +0.31
3000 +1.43 +1.49