摘要:
Apparatus for generating supervisory test signals in the interval between the beginning of vertical blanking and the beginning of vertical sync in a television synchronizing waveform, so as to free for other communication purposes those portions of the waveform such test signals conventionally occupy.
摘要:
Acknowledgement apparatus for use in a radio postal system of the type employing an orbiting relay satellite for transmission, including receiver reply circuits operating at a narrower bandwidth and with a lower signal-to-noise ratio than are associated with corresponding transmitter message circuits so as to enable use of reply circuits of substantially reduced power.