Product Info
PTR for VHF-4000 and VDL-2000 Data Radios
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©2000 Rockwell Collins, Inc Page 20 of 61
7)
Store the values used for TFM parameters #18 and #19 in FLASH memory.
Repeat for every 1 MHz step through 136.500 MHz using the previous band values as the initial values
6.3.16.3 MODE 2 RF POWER
1)
Tune the UUT to Channel 118.500.
2)
Set UUT to SSB mode
3)
Set TFM parameters # 15 and 16 (D8PSK I_Channel Gain and Q_Channel Gain) to $00.
4)
Increase the I_Mod TFM (#15) until 10.0 + 0.08 Watts is measured at the RF output and record value.
5)
Set TFM parameters # 15 (D8PSK I_Channel Gain) to $00.
6)
Increase the Q_Mod TFM (#16) until 10.0 + 0.08 Watts is measured at the RF output and record value.
7) Repeat for every 1 MHz step through 136.500 MHz.
8) Store the values used for TFM parameters #15 and #16 in FLASH memory.
6.3.16.4 D8PSK QUADRATURE MISMATCH
1)
Tune the UUT to 118.5 MHz.
2)
Set UUT to SSB mode
3)
Ground the PTT line (Pin 41 VHF-4000, Pin 35 VDL-2000). Null the lower amplitude sideband of the
RF output by adjusting the D8PSK Quadrature Mismatch TFM (#28) while monitoring the output on a
spectrum analyzer. The lower amplitude sideband must be at least –40 dBc relative to the higher
amplitude sideband. The Q mod TFM (#16) determined in earlier adjustments may be adjusted as
required to aid in achieving the required null value of –45 dBc for the lower sideband.
4)
Repeat for every 1 MHz step through 136.500 MHz using the previous band values as the initial values
for TFM #28.
5)
Store the values used for TFM parameter #28 and #16 (if changed from initial value) in FLASH
memory.
6.3.17 Mode 2 AGC Calibration
8) Set Standard ARINC Configuration at 118.5 MHz.
9) Set Standard RF Generator setting at current frequency with CW signal at –90.5
dBm.
10)
Set Standard Discrete Configuration.
11)
Read receiver AGC value
12)
Store this value in Flash memory for TFM parameter 33 (Mode 2 – 90.5 dBm level)
13)
Readjust generator RF level for –91.5 dBm
14)
Read receiver AGC value
15)
Store this value in Flash memory for TFM parameter 34 (Mode 2- 91.5 dBm level)
16)
Repeat for every 1 MHz step through 136.500 MHz
6.3.18 Flash Update
1) If not previously performed, write all TFMs that have been adjusted during previous alignment steps to
Flash Memory.
7.
Final Test Requirements
Final Test may be performed manually or with the automatic alignment system (CATS-
21) executing DGS-005 or any combination thereof.
Unless otherwise specified, disable the squelch, connect a VHF signal generator to the
antenna input, and connect an audio distortion analyzer to the audio output (VHF-4000
combined audio pins 25 and 26, VDL-2000 RX_AUDIO_OUT pins 33 and 19).