TM 11-5820-803-12
Table 3-1. Operator Controls, Indicators, and Connectors-Continued
Controls, indicators, or connectors
Function
Position 5-Connects the internal error comparator to monitor the
alternate data and clock outputs.
Position 6 Connects the internal error comparator to monitor LOS/cable
receiver and decoder output.
Position 7-Same as position 4.
MANUAL/OFF/AUTO, three position toggle switch
MANUAL-Causes internal error comparator to sample input data and
synchronize comparator circuits.
OFF-Disables automatic mode.
AUTO-Activates automatic resynchronization of internal error
comparator when error rate measurement exceeds 25 percent.
ERROR connector
Provides an output pulse from the internal error comparator for each bit
error detected.
SYNC connector
Provides a sync pulse from the internal 2047 bit sequence
(1/2047 of INPUT DATA RATE switch setting).
CLOCK connector
Provides the clock signal from the internal error comparator.
RECEIVE Section
SYMBOL RATE thumbwheel switch
Selects receive symbol rate of 19.200 kb/s to 9.9999 Mb/s in
three bands:
Band 1-19.200 kb/s to 99.999 kb/s
Band 2-100.00 kb/s to 999.99 kb/s
Band 3-1.0000 Mb/s to 9.9999 Mb/s
ERROR CODING, three position rotary switch
INTERNAL-Selects the internal rate one-half decoder.
NONE-Selects a straight through path without error correction
decoding.
EXTERNAL-Selects an external decoder.
POWER section
10 AMP fuse
Overload protection.
SPARE fuse
Spare 10 amp fuse.
Indicator
Illuminates when power is applied.
ON toggle switch
ON-Applies ac power to the PSK Modem.
Controls Behind Front Panel
STD/CLK/ICF switch
Enabled by placing the TRANSMIT SOURCE switch in the
OPERATE position. Selects either the direct digital (standard) data input or the LOS/cable input for transmission over the link. Also
determines whether transmitter timing is derived from the input data
or an input clock.
STD-Selects the direct digital (standard) data input for transmission and
timing derivation.
CLK-Selects the direct digital (standard) data input for transmission and
the direct digital clock input for timing derivation.
ICF-Selects the LOS/cable input for transmission and timing derivation.
DIFF ENCODE, two position toggle switch
ON-Activates Differential Encoder in transmitter.
OFF-Disables Differential Encoder in transmitter.
DIFF DECODE, two position toggle switch
ON-Activates Differential Decoder in receiver.
OFF-Disables Differential Decoder in receiver.
Section II. OPERATION UNDER USUAL CONDITIONS
3-3.
General
a. Preliminary Starting Procedure. The preliminary
The PSK modem may be used for self-testing, link-
starting procedure (para 3-4) prepares the modem for
testing, or duplex digital communications. The required
operation.
procedures are included in this section. Before placing
b. Self-Test. The self-test procedure (para 3-5) is
the modem into operation, the site requirements must be
performed to ensure the modem is operating properly.
reviewed, and the normal operational switch settings
Self-test is performed as a part of the routine modem
must be entered per table 3-2. Purpose of the various
maintenance cycle, the preliminary starting procedure,
modes are briefly described in following paragraphs.
3-4
