B4.6 T855 Functional Testing M8SL2-00-002-812
© Copyright Tait Electronics Limited August 2004. All rights reserved.
4.7 Noise Mute (If Linked In)
Rotate RV230 (front panel gating sensitivity) fully anticlockwise.
Apply an on-channel signal from the RF generator at a level of –110dBm with
±3kHz deviation (±2.4kHz) [±1.5kHz] at 1kHz.
Increase the RF level in 1dB steps, checking that the mute opens for an RF input
level of approximately –105dBm.
Turn the RF off and check that the mute closes.
Rotate RV230 clockwise and check that the mute opens.
Reset RV230 to give the required opening sinad.
Caution: Some RF generators can cause a false opening of the mute because the
generator produces a burst of noise when the attenuation range
changes. To correct the problem you will have to change generators.
4.8 RSSI (If Fitted)
Apply an on-channel signal from the RF generator at a level of –110dBm with
±3kHz deviation (±2.4kHz) [±1.5kHz] at 1kHz.
Using a high impedance DMM, check that the RSSI output voltage on pin 5 of
D-range 1 (PL100) is 2V (nominal).
Vary the RF level in 5dB steps and check that the RSSI output voltage changes at a
rate of approximately 10dB/V over the range of –115dBm to –70dBm (refer to Fig-
ure 4.2 for RSSI voltage vs signal strength).
Figure 4.2 T855 RSSI Voltage vs Signal Strength
RF Level (dBm)
-130 -120 -110 -100 -90 -80 -70 -60
1
2
3
4
5
6
7
8
RSSI Voltage
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