ZETRON 025-9581M, Руководство по установке и обслуживанию

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Appendix A: Details of Model 6203/6204 Hardware
168 025-9581M
FFSK IN (R62)
This pot is a secondary receive level adjustment for the FFSK input. It should initially be
turned completely counterclockwise (its lowest setting). It is only used in systems
employing a Model 26 as a backup dispatch method.
Before doing the necessary adjustment, verify that the receive impedance jumpers JP8 and
JP10 have been properly set (see
Transponder Board Jumpers on page 160) and that the
Alerting system primary Model 26 is sending an FFSK test tone so the Model 6203
receive level can be measured. Verify that the Model 26 FFSK transmit level has been
properly set first.
4-RCV (R107)
Turn R135 fully counterclockwise and R107 fully clockwise. Measure the voltage at TP1,
which should be 1.0 Vp-p (0.35 Vrms). If the voltage is too low, adjust R62 clockwise
until it is 1.0 Vp-p (0.35 Vrms). If the voltage is too high, adjust R107 counterclockwise
until it is 1.0 Vp-p (0.35 Vrms).
COR (R84)
This pot adjusts the COR detect circuit and needs to be adjusted whether RX COR input is
being used or not. This pot can usually be set to about its middle position. The important
thing is that the COR/VOX LED (DS33) is off when nothing is connected to the RX COR
input (J5-1) and goes on when it is grounded.
When making this adjustment JP9 should be in the “A” position (COR pulled up) and JP3
should be in the “A” position (VOX disabled).
VOX (R86)
This pot adjusts the VOX detect circuit and needs to be adjusted regardless of the
communication mode being used. This pot is like a squelch on a radio and should be
adjusted so VOX does not detect background noise during times of channel inactivity
(DS33 off). However, VOX should detect channel activity (DS33 on) when the channel is
busy and voice/FFSK signals are being received.
When making this adjustment, input RX COR (J5-1) should not be connected to anything,
JP9 should be in the “A” position (COR pulled up), and JP3 should be in the “B” position
(VOX enabled). Use COR/VOX LED (DS33) to monitor when channel activity is being
detected. If there is no LED activity when the input is inactive and this pot is fully
counterclockwise, then further audio tests should be done at a later time for dispatch
announcements with a lot of background noise. This is a qualitative judgment and is a
Note Do not forget to put JP3 back to position “B” when the COR
adjustment has been completed.