Edward H Callaghan

US Patent:

45216460, Jun 4, 1985

Filed:

Dec 2, 1981

Appl. No.:

6/326472

Inventors:

Edward P. Callaghan - New Hyde Park NY

International Classification:

G10L 100

US Classification:

375122

Abstract:

Bandwidth reduction by simple spectrum folding (i. e. , adding the reversed-spectrum signal to the original signal) causes spectrum ambiguties and cancellations which are avoided by encoding, i. e. , first "earmarking" the original signal by adding to the original signal its squared signal, then angle-modulating the reversed-spectrum earmarked-signal before adding it to the earmarked signal. Bandwidth expansion for signal reconstruction involves decoders which use the encoder in a feedback loop.

US Patent:

20180287847, Oct 4, 2018

Filed:

Mar 30, 2017

Appl. No.:

15/474329

Inventors:

Edward P. Callaghan - New Hyde Park NY, US

International Classification:

H04L 27/38
H04L 27/26
H04L 27/34

Abstract:

Signal extrication of a pair of quadrature amplitude modulated signals, of a particular carrier frequency and phase constant, is accomplished by the use of a discriminator-mixer circuit, where the carriers and sidebands of the said pair of quadrature amplitude modulated signals are intermingled with similar and/or nondescript signals containing sinusoidal components and can not be selected for signal demodulation by normal detection means without distortion of the information carried by these signals, by equally splitting all input signals to the discriminator-mixer circuit into two independent circuit paths that contain identical components but one independent circuit path performs a complementary signal processing function with respect to the other independent circuit path resulting in a counterbalance between the two paths, thereby generally canceling all output signals of the said discriminator-mixer circuit, with the exception of the said pair of quadrature amplitude modulated signals which are not canceled because of the singular signal nullification property of a product detector circuit, that is a component in each of the said independent circuit paths, by the use of heterodyne techniques between the input signals to the said product detectors and the synchronized local oscillator output pair of quadrature sinusoidal signals of the said particular frequency and phase constant, that cause a counterbalance null in each of the two paths and allowing only the said desired pair of quadrature amplitude signals to appear at the output of the discriminator-mixer circuit.