Abstract: A bidirectional serial port for digital audio data includes a cable connector for coupling the port to a cable, a cable driver having a serial digital audio signal as an input and also having an output, a receiver having an input and an output, and an impedance and level matching network coupled to the output of the cable driver, the input of the receiver, and the cable connector. The port can be selectively configured either as an input port by causing the impedance and level matching network to act as a cable termination or as an output port by allowing the serial digital audio signal to pass through the cable driver and the impedance and level matching network to the cable connector.

Abstract: A power envelope shaping device for joining to a serial control output is sclosed. Multiple power switcher modules are joined to a plurality of incremental power sources and controlled by the power select circuitry module. In this way, each power switcher module can provide power from at least one of the incremental power sources on command from said power select circuitry module. The power switcher module outputs are joined together in order for providing varying power levels in accordance with a preprogrammed power envelope shape.

Abstract: A target echo simulator with reverberation and ambient noise for testing an ctive sonar system. A transmit enable pulse from a sonar transmitter establishes a sequence of operations in which a target echo generator, reverberation generator and ambient noise generator produce a composite signal. The target echo generator produces a pulse modulated output pulse of a characteristic sonar frequency. The reverberation generator produces an amplitude modulating or envelope controlled output at a frequency of a carrier that is offset from the target echo carrier frequency. An ambient noise generator constantly produces ambient noise. A summing amplifier combines the generated signals to produce a composite signal for transfer to a receive connection on the active sonar system.