Voice and Data Signals

Figure 1-9.-UHF-2 antenna select panel. Figure 1-10.-UHF block diagram. accomplished through the control box and the A516 communications system selector. Some of the peripheral equipment include the AN/AIC-22 intercommunication system, the AN/AGC-6 teletypewriter set (TTY), the AN/ACQ-5 data terminal set (DTS), the AN/ASA-76 generator transmitter group (CASS), and the security equipment TSEC/KY-28 or TSEC/KY-58. In general, both radio sets are UHF transceivers that provide two-way voice and data communication in the frequency range of 225.000 to 399.975 MHz. They automatically tune 7,000 channels at 0.025-MHz intervals. Built in self-test circuits detect the presence or absence of required operation signals and voltages, then illuminate fault indicators upon detection of faults. Voice and Data Signals Voice and data signals at the UHF-2 radio set are linked to the TTY, ICS, and DTS. The UHF security unit is linked between both radio sets and the ICS. This security unit ciphers and deciphers secure voice information. The UHF-2 radio set is used as a backup transmitter for sonobuoy command signals for the CASS system. The secure switching matrix controls the signal flow between the signal processing equipment and the voice, data source, and monitoring equipment. Transmit Functions During transmit, the keying and transmit signals from the voice or data source are coupled by the COMM switching matrix to the UHF RT. In the UHF-1 set, the keying signal is interlocked by the UHF-1 RF switch. The voice or data signal modulates the carrier signal generated in the RT, and the output signal is amplified and coupled to the antenna. The UHF-1 output goes through the UHF falter and UHF-1 RF switch to the antenna. UHF-2 output goes through the UHF filter and the UHF-2 RF switch. To provide operating frequency and mode control information, both radio set control boxes generate a digital bit stream that is decoded in the radio’s RT. This decoded stream gates the appropriate selected carrier modulation mode and operating frequency. It also gates input voice or data signals by activating the appropriate lines in the RT for the selected operating mode. The COMM system selector interfaces the UHF-2 radio set with the other systems by controlling the keyline and voice or data signal relay gates in the COMM switching matrix. The UHF-1 set control and the UHF- 1 voice selector interface the UHF-1 radio set with the voice or data sources. The satellite communications (SATCOM) relay panel is activated to the SATCOM mode of operation by the UHF-1 control box. The control sends an FM select signal to the relay panel, and this switches the panel to the SATCOM mode. The UHF-1 RT is connected to the top antenna through the internal preamplifier to receive the UHF RF signals. UHF-DF Operation The UHF-DF operation is accomplished by connecting the UHF-1 radio set to the AN/ARA-50 automatic direction finder set. The ADF received signals are routed through the UHF-1 RT, complete with sidetone to the ICS system for monitoring. During UHF-DF operations, the operator can break in to the mode to transmit. When the mike is keyed to transmit, the UHF-1 RT is automatically connected to the top UHF antenna for transmission. When the mike key is released, the UHF-1 RT is automatically switched back to the ARA-50 antenna for resumption of DF operations. UHF-1 Receive During receive, the RF from the top antenna is coupled through the SATCOM relay panel, the RF SWITCH, and the UHF filter to the RT. In the RT, the signal is applied to both the main receiver and the guard receiver. The main receiver consists of two modules-the receiver and a 70-MHz I/O. The receiver is capable of providing reception of 7,000 channel frequencies. The 1-15