NORMARC 7050, Руководство пользователя

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TRANSMITTER
1-4
21464-5
NORMARC 7050
MARKER BEACON
TX 1373A Transmitter ©1999 Navia Aviation AS
(See block diagram Figure1-1)
1.1.3 Building blocks
(See block diagram Figure1-1)
OSCILLATOR
The oscillator is controlled by the Transmit signal from the LF generator. When Transmit is
low, a controllable voltage generator turns the internal oscillator 12V voltage on. +12 VDC is
then applied to the collector of a bipolar transistor, which is the active device of the oscillator.
A 75 MHz crystal is connected in the feedback path together with a resonance circuit.
The output signal is amplified to approximately 0 dBm through a RF gain block.
Signals in:
ON/OFF to switch oscillator on.
Signals out: RF to AGC
AUTOMATIC GAIN CONTROL
The AGC circuitry is designed to adjust the signal level from the oscillator to the PA. The sig-
nal from the oscillator is fed to one of the ports of a dual gate MOSFET. The signal enters the
In From Description
IOD[7:0] MO 1374
Parellel data bus for communication between TX
1/2, CI and MO1
~TXCS MO 1374 Transmitter card select
~TXWR MO 1374 Write strobe for IO bus
~TXRD MO 1374 Read strobe for IO bus
TX_ADR CI 1376 Transmitter select
TX_ON MO 1374 Transmitter on/off
AMUX_A[3:0] MO 1374 Used to select measurement
~RMS_LEV[1:0] MO 1374 Signals access level for RMS
Out In Description
RF_OUT Antenna Radio signal
∼
TX_FB MO 1374 Signal tells monitor that transmitter is active
A_TX[P,N] RMS RMS analogue test signals
∼
TXCSB MO 1374 Transmitter card select back
Bidirectional To/From Description
TX_CTRL_BUS MO 1374 Changeover Control (TX_ADR), transmitter on/
off (TX_ON), card select back (TXCSB), feed
back (TX1/2_FB)
Power in From Description
V20P PS 1375 +20 VDC to PA
V12P PS 1375 +12 VDC
VDD PS 1375 +5 VDC
GND PS 1375 Analogue ground
V12N PS 1375 -12 VDC