RFL 9780 RFL Electronics Inc.
April 8, 2003 12-2 (973) 334-3100
12.2 SPECIFICATIONS
As of the date this manual was published, the following specifications apply to all RFL 9780 IF/BF
modules. Because all RFL products undergo constant refinement and improvement, these specifications
are subject to change without notice.
Frequency Range: 30 to 535 kHz; frequency is adjustable in 250-Hz steps.
Bandwidth: 3700 Hz.
Input Impedance: 1574 ohms nominal.
Input Level: 63 mVrms when receiving 1/10 full power transmit signal.
200 mVrms when receiving full power transmit signal.
Output Impedance: 100 Ohms.
Output Signal: 4-kHz baseband.
12.3 THEORY OF OPERATION
The main function of the RFL 9780 IF/BF Module is to convert the incoming rf signals to a 4-kHz bf.
Basically, the RFL 9780 IF/BF performs the frequency conversion by first up-converting the signal to
5.12 mHz, by using a programmable synthesized local oscillator. The signal is then fed to a crystal
filter that passes the lower 3700-Hz wide sideband of the 5.12-mHz signal.
Next, the signal is down-converted to a 2-kHz carrier, and then to the 4-kHz bf. The bf signal is passed
on to the RFL 9780 Carrier Level Indicator Module (Section 13) for further processing.
A block diagram of the RFL 9780 IF/BF Module appears in Figure 12-2, controls and indicators appear
in Figure 12-3, a component locator drawing appears in Figure 12-4, and a schematic diagram appears
in Figure 12-5.
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