carrier telephony การใช้

The Negative feedback amplifier allowed Bell system to reduce overcrowding of lines and extend its long-distance network by means of carrier telephony.
The baseband signal could be 300-3000 Hz audio, or it could be video extending to 100 MHz, or it could be a highly multiplexed carrier telephony signal extending into the GHz range.
Various other sets such as the B70 UHF carrier telephony relay, C11 / R210 HF transmitter / receiver for Royal Signals use, and the Marconi transmitter D11 and its associated receiver, the R230 were commercial developments adopted as standard sets by the British services.
He also conducted research on ultra-short waves, electronics, and piezoelectric devices, and invented important modulation systems including the constant potential system, the grid modulation system, the rectifier modulation system used in carrier telephony, and the constant-current or Heising modulation system, which was standard on most early radio telephone transceivers.
In U . S . common carrier telephony service, a toll center designated " Class 4C " is an office where assistance in completing incoming calls is provided in addition to other traffic; a toll center designated " Class 4P " is an office where operators handle only outbound calls, or where switching is performed without operator assistance.