FEED-FORWARD, ERROR-CORRECTING SYSTEMS

• US 3,815,040 A
• Filed: 03/02/1973
• Issued: 06/04/1974
• Est. Priority Date: 03/02/1973
• Status: Expired due to Term

• Current Assignee: Harold Seidel
• Original Assignee: Harold Seidel
• Inventors: Seidel, Harold
• Primary Examiner(s): Saalbach, Herman Karl
• Assistant Examiner(s): Mullins, James B.
• Application Number:
  US05/337,670
• Time in Patent Office: 459 Days
• Field of Search: 330/149,151 332/48,37R 325/472,476 328/163
• US Class Current: 330/149
• CPC Class Codes: H03F 1/3229 using a loop for error extraction and another loop for error subtraction
• CPC Class Codes: H03F 2200/198 A hybrid coupler being used as coupling circuit between stages of an amplifier circuit
• CPC Class Codes: H04B 3/06 by the transmitted signal
• CPC Class Codes: H04J 1/12 Arrangements for reducing cross-talk between channels in line transmission systems H04B3/32; in cables or lines H04B3/26 - H04B3/30

Abstract

In a feed-forward, error-correcting system in accordance with the present disclosure, the error signal is formed by comparing the modulation component of the signal before and after signal processing. The error signal is then used to modulate the main signal so as to reduce the modulation error components introduced by the signal processing circuits.

Claims

1. A feed-forward, error-correcting system comprising:

means for dividing the input signal to said system into two signal components;

means for coupling one of said signal components to a signal processing circuit;

means for comparing the modulation components of the output signal from said signal processing circuit and the modulation components of said other input signal component, and for forming an error signal corresponding to the spurious modulation components introduced by said signal processing circuit;

modulation means, responsive to said error signal, for generating in the output signal from said signal processing circuit modulation components equal in amplitude but 180* out of phase with the spurious modulation components introduced by said processing circuit;

means for coupling said error signal and the output signal from said processing circuit to said modulation means; and

means for extracting a corrected output signal from said modulation means.

2. The system acccording to claim 1 wherein said signal processing circuit is an amplifier.

3. The system according to claim 1 wherein said input signal is amplitude modulated.

4. The system according to claim 1 wherein said input signal is phase modulated.

5. The system according to claim 1 wherein said input signal is frequency modulated.

6. A feed-forward, phase error-correcting amplifier comprising:

means for dividing the input signal to said amplifier into a main signal component and a reference signal component;

means for amplifying said main signal component;

means including a synchronous phase detector, for comparing in time coincidence the phase of a portion of the output signal from said amplifying means and the phase of said reference signal component, and for forming an error signal proportional to the difference in said phases; and

means for phase modulating the output signal from said amplifying means with said error signal in a sense to reduce the phase error introduced by said amplifying means.

7. The amplifier in accordance with claim 6 including a time delay network for delaying said reference signal an amount of time such that said reference signal and said portion of output signal arrive at said phase detector in time coincidence.

8. The amplifier in accordance with claim 6 including amplitude limiters for maintaining said reference signal and said portion of output signal at constant amplitudes.

9. The amplifier according to claim 6 including a phase shifter for establishing zero error signal under conditions of no phase error.

10. A feed-forward, amplitude error-correcting system comprising:

means for dividing the input signal to said amplifier into a main signal component and a reference signal component;

means for amplifying said main signal component;

means for dividing the output signal from said amplifying means into two unequal signal portions;

first means for amplitude detecting the smaller of said signal portions;

second means for amplitude detecting said reference signal;

means for differencing the output signals from said two detecting means and forming an error signal proportional to their difference; and

means for amplitude modulating the larger signal portion with said error signal in a sense to reduce the amplitude error introduced by said amplifying means.