If Interface; Synthesizer Interface; Wj-8718A/488M Option; Wj-8718A/232M Option - Watkins-Johnson Company WJ-8718A/MFP Instruction Supplement

GENERAL DESCRIPTION
1.1. 3 IF INTERFACE
WJ-8718A/MFP
The IF Interface (MFP-A3) plugs· into the WJ-8718A I/O Motherboard (A6)
replacing the Front Panel Interconnect Board (A2).
The IF Interface contains storage registers for detection mode, IF bandwidth, and
gain mode data. In addition, the interface couples signal strength voltage for the front panel
meter to the Front Panel Switch Encode Board, and switches the line and ISB audio for the front
panel phone jack. If an optional 232M or 488M I/O Interface is used, the IF Interface provides
analog-to-digital conversion of signal strength voltage and digital-to-analog conversion of RF
gain voltage.
1.1.4 SYNTHESIZER INTERFACE
The Synthesizer Interface (MFP-A4) plugs into the WJ-8718A I/O Motherboard
(A6), replacing the standard Manual Tuning Up/Down Counter Board (A6A!). The Synthesizer
Interface houses the Inte18085A Microprocessor, EPROM for storage of microprocessor
program and RAM for storage of program variables. The microprocessor, reset at power-up,
executes the program stored in EPROM. The program is designed to implement the functions of
the front panel by translating the switch settings into digital data for the signal processing
circuits in the receiver. In addition, storage registers provide RF and BFO frequency data to
the synthesizer section of the receiver.
1.1.5 WJ-8718A/488M OPTION
The 488M Option extends the functional capability of the MFP Option to include a
talk/listen compatibility with the IEEE Standard 488-1975 format. The 488M Option consists of
the Type 796075 I/O Interface (488M-A3) with the cables, connectors, and hardware to install
the interface in the receiver. In addition, two EPROMs programmed to included remote
operation are provided to replace the EPROM Ul and U2 on the Synthesizer Interface
(MFP-A4).
The I/O Interface is plugged into the I/O Motherboard (A6) and is cable-connected
to a digital connection (488-Jl) on the rear panel and to the IF and Synthesizer Interface Boards
(MFP-A3 and A4). The I/O board handles the bidirectional transfer of data on the 488 bus.
1.1.6 WJ-8718A/232M OPTION
The 232M Option extends the functional capability of the MFP Option to include
talk/listen compatibility with the EIA Standard RS-232/C format. The 232M Option consists of
the Type 796037 I/O Interface Board (232M-A3) and the necessary cables, connectors, and
hardware to install the board in the receiver. In addition, EPROMs programmed to include
remote (232) operation as well as MFP operation are provided to replace EPROM Ul and U2 on
the Synthesizer Interface (MFP-A4).
The I/O Interface Board (232M-A3) is plugged into the I/O Motherboard (A6) and is
attached via cable to the rear panel digital connections and the IF and Synthesizer Interface
Boards (MFP-A3 and A4). The I/O Interface Board handles the bidirectional transfer of data on
the RS-232/C interface, allowing remote control of up to 32 "daisy chain" configured receivers,
as shown in Figure 1-2.
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