| 摘要 |
An improved marine radio telephone is disclosed having a microphone, display, speaker, and controls. The controls include switches and a keyboard located together with a display in a panel, a microphone conveniently located as to the front panel, and a push-to-talk switch incorporated in the microphone. A panel printed wiring board is provided for the control circuits. Digital logic circuits, including a special purpose microcomputer and a power supply mounted on a second printed wiring board, interface with the control circuits and display. The control circuits include circuit blocking means which can be readily removed to permit, when authorized, transmission on Coast Guard auxiliary channels 21, 23, 81, 82, and 83. A frequency synthesizer interfaces between the logic circuits and a transmitter and receiver. The synthesizer and receiver are mounted on a third PWB, and the transmitter is mounted on a fourth printed wiring board. The special purpose microcomputer has an on-chip ROM and RAM processing capability which allows continuous scanning of at least one preselected channel in addition to the scanning of the emergency channel "16" and the automatic switching of power from 25 watt to one watt with the selection of one of the three channels requiring one watt operation.
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