SBE SB-36 OPERATION MANUAL
5. 0 THEORY OF OPERATION
5. 1 GENERAL
5.1.1
Figure 5.1 shows the basic transmitter receive signal paths and the
printed circuit boards associated with each. The SB-36 Transceiver is
comprised of a power amplifier assembly, accessory power supply, and
one each of the following circuit boards:
Drive RF/Pre-Mixer and Oscillator Board, Counter Unit, VFO Oscillator,
carrier Oscillator Board, Double Sideband Amplifier/Crystal Filter/Noise
Blanker Board, Microphone Amplifier and Side Tone Oscillator Board,
Receiver IF Amplifier and AGC Amplifier Board, 20 volt Regulator
Board, AF Power Amplifier Board, and VOX and ANTI-TRIP Board.
The printed circuit board relationship in respect to transmit or receive
signal paths is shown in Figure 5.1. In the transmit mode, the signal is
routed from the microphone through the MIC AMP Board, Double
Sideband AMP/Crystal Filter Board, Driver RF/Pre-Mix and Oscillator
Board, and PA Assembly. A more detailed explanation of the transmit
signal path is covered in paragraph 5.2. In the receive mode the signal
is routed from the antenna connector through the PA assembly, Driver
RF/Pre-Mix and Oscillator Board, Double Sideband Amplifier / Crystal
Filter Board, Receiver IF Amplifier and AGC Amplifier Board, Audio PC
Board, to the external speaker jack. A more detailed explanation of the
receiver signal path is covered in paragraph 5. 3.
Frequencies generated by the BFO (9 MHz) Board are routed to the
double sideband amplifier and noise blanker board and from there are
routed to the driver RF/Pre-Mixer and Oscillator Board. Frequencies
generated by the VFO are routed to the Driver RF/Pre-Mixer and
Oscillator Board. The Theory of Operation section employs the use of
more detailed block diagram's than Figure 5.1. Complete schematics
are also contained in Section 7 and should be used in conjunction with
the description of the transmitter and receiver circuitry contained in the
following paragraphs.
NoobowSystems Lab. Tomioka, Japan 2003 http://www.noobowsystems.com/ Page 20 / 56
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