LSI portable transceiver

This paper describes the Flight Deck Communications System Portable Transceivers developed for the U.S. Navy to provide secure communications in the hostile environment of an aircraft carrier flight deck. Extensive use of custom integrated circuits was necessary to simultaneously achieve the electrical performance necessary to simultaneously achieve the electrical performance and weight requirements dictated by the military environment. Fourteen unique custom bipolar and CMOS integrated circuits were developed for the transceivers, including IF, Synthesizer, audio and control functions. Leadless chip carriers on both ceramic and printed circuit card modules were selected for the packaging approach. Additional benefits derived from the use of custom integrated circuits include reduced manufacturing costs, high reliability and survivability in the military environment. The mission of the Flight Deck Communications System radio equipment is to provide secure point-to-point communications to personnel requiring a high degree of mobility and close contact with their superiors while performing their duties in the launch and recovery operations environment aboard an aircraft carrier. Other uses include below deck operations requiring man on the move communications. The launch and recovery operations require a helmet transceiver that provides secure intelligible communications in a 135 dBa acoustic noise environment and a 200 volt/meter RF field. The system architecture developed to satisfy this requirement uses digital data as the information format and is derived from an analog to digital conversion of speech. The conversion algorithm has been optimized to achieve maximum intelligibility and speech recognition with a minimum data rate. Data encryption/decryption is performed by a government furnished device. The transmitter modulation format utilizes frequency shift keying. The custom integrated circuit radio consists of a UHF filter/ amplifier module, a frequency synthesizer module, an IF converter module, a data encryption/decryption module, and an audio speech processing module. Each module consists of a number of custom integrated circuits as well as discrete components. The UHF filter/amplifier module accepts the input from the antenna where the signal passes through an electronic transmit/receive switch prior to amplification and narrowband preselection. The IF converter module consists of an IF/converter chip, a limiter chip and a digital discriminator modem chip. The audio speech processing module contains a continuously variable slope detection chip, as well as custom audio chips, for amplification and audio level readjustment. The frequency synthesizer contains all the circuits necessary to generate any one of 500 frequencies in the 340-390 MHz band including a digital divider chip, a loop filter chip, and a standardizer chip. The power amplifier module develops 100 mW of output power for delivery to the antenna. Each of the modules described above occupies approximately 1.2 cubic inches, and when assembled in its enclosure, along with batteries, speaker and controls, occupies 35 cubic inches. The extensive use of low power custom integrated circuits has reduced power consumption by a factor of 4 to 1 over previous designs using hybrid and discrete components.