×

Subscriber RF telephone system for providing multiple speech and/or data signals simultaneously over either a single or a plurality of RF channels

  • US 5,734,678 A
  • Filed: 10/02/1996
  • Issued: 03/31/1998
  • Est. Priority Date: 03/20/1985
  • Status: Expired due to Fees
First Claim
Patent Images

1. An apparatus for providing a plurality of voice signal channels on a plurality of forward direction carrier frequencies of a terrestrial RF telephone system, each of said forward direction carrier frequencies containing a plurality of slots, each of said forward direction carrier frequencies having an associated predetermined bandwidth which is designed to accommodate one analog voice signal channel therein, said apparatus comprising:

  • a base station comprising;

    a plurality of circuit paths for receiving a plurality of forward direction digitized voice signals from a public switched telephone network;

    a plurality of compressors for respectively compressing each of said forward direction digitized voice signals by analyzing the speech content of said forward direction digitized voice signals and by using voice compression to form respective forward direction compressed digitized voice signals, each compressed digitized voice signal having a bit rate of less than 16 kb/s;

    a processor for assigning each of the compressed digitized voice signals a dynamically assigned frequency/slot;

    a plurality of channel controllers, each for sequentially combining said respective forward direction compressed digitized voice signals into a single transmit channel bit stream, with each of the respective forward direction compressed digitized voice signals occupying a respective repetitive sequential time slot in the transmit channel bit stream;

    a plurality of modulators for modulating each of said forward direction carrier frequencies with said transmit channel bit stream, each of said modulators using M-ary modulation to transmit at least 2 bits/symbol, wherein a carrier frequency within a portion of each said slot remains unmodulated by said transmit channel bit stream; and

    a transmitter for RF transmitting said forward direction modulated frequency carriers to at least one subscriber station, each of said transmitted modulated forward direction carrier frequencies residing within said predetermined bandwidth and capable of carrying in the forward direction at least two bidirectional simultaneous conversations;

    wherein at least part of said slot portion unmodulated with said transmit channel bit stream provides a phase reference signal.

View all claims
  • 0 Assignments
Timeline View
Assignment View
    ×
    ×