Time sharing frequency synthesizer

• US 4,694,466 A
• Filed: 06/03/1985
• Issued: 09/15/1987
• Est. Priority Date: 06/03/1985
• Status: Expired due to Term

• Current Assignee: ITT Corporation (ITT, Inc.)
• Original Assignee: ITT Defense Communications
• Inventors: Kadin, Joseph
• Primary Examiner(s): NOT, DEFINED
• Assistant Examiner(s): Huseman, M.
• Application Number:
  US06/740,603
• Time in Patent Office: 834 Days
• Field of Search: 375/1, 375/2.2, 375/88, 375/45, 375/58, 375/23, 455/165, 455/189, 455/209, 455/76, 455/82, 331/179, 328/14, 370/29, 370/38
• US Class Current: 375/136
• CPC Class Codes: H04L 27/26 Systems using multi-frequency codes H04L27/32 takes precedence

Abstract

A frequency synthesizer circuit operates in a time shared mode. Thus the frequency synthesizer circuit operates to transmit and/or receive a particular frequency for a chosen small amount of time and then sequentially transmits and/or receives the other frequencies for chosen small amounts of time. After all the chosen frequencies have been transmitted and/or received the synthesizer circuit will return to the first of frequency and begin to repeat the process in cyclical fashion.

Claims

1. A time sharing frequency synthesizer circuit, comprising:

means for synthesizing a plurality of desired frequencies one at a time for predetermined intervals in a desired sequence, said means comprising a reference oscillator, a microprocessor containing values corresponding to a table of desired output frequencies for a frequency synthesizing device, said microprocessor being connected to an output of said reference oscillator, and a frequency synthesizer which is connected to an output of said reference oscillator and an output of said microprocessor and which contains circuitry for converting the output of said reference oscillator into any desired frequency,

means for heterodyning each of said desired frequencies with one or more signals with frequencies within a desired bandwidth to generate intermediate frequencies at a sample rate consistent with the Nyquist criteria of sampling at a frequency at least twice the effective bandwidth; and

means for discriminating among said intermediate frequencies.

2. The circuit of claim 1, further comprising a frequency hopping filter connected to receive incoming signals and to convey the incoming signals which pass therethrough to said means for heterodyning, said hopping filter being connected to and controlled by said microprocessor which contains values corresponding to a table of desired center frequencies for said frequency hopping filter.

3. The circuit of claim 2, further comprising clock means for sending time signals to said microprocessor and said frequency synthesizer.

4. The circuit of claim 2, further comprising a second frequency hopping filter connected to the output of said reference oscillator and functioning to restrict outgoing signals from the circuit within desired bandwidths and to convey outgoing signals which pass therethrough to a second heterodyning means, said second frequency hopping filter being connected to and controlled by said microprocessor which contains values corresponding to a table of desired center frequencies for said second frequency hopping filter.

5. The circuit of claim 4, further comprising a duplexer connected to said heterodyning means and to said second heterodyning means enabling signals to be transmitted and received by said time sharing frequency synthesizer circuit through a single antenna.

6. The circuit of claim 2, further comprising means for multiplexing in sequential fashion signals which have passed through said heterodyning means, said means for multiplexing conveying said multiplexed signals to different channels.

7. The circuit of claim 6, further comprising clock means for sending timing signals to said microprocessor and said frequency synthesizer.