Method and means for modulating waves

• US 4,433,312 A
• Filed: 12/18/1981
• Issued: 02/21/1984
• Est. Priority Date: 12/18/1981
• Status: Expired due to Fees

• Current Assignee: Leonard R. Kahn
• Original Assignee: Leonard R. Kahn
• Inventors: Kahn, Leonard R.
• Primary Examiner(s): Heyman, John S.
• Assistant Examiner(s): Biase, Nicholas
• Application Number:
  US06/332,018
• Time in Patent Office: 795 Days
• Field of Search: 332/17, 332/41, 332/44, 332/48, 332/52, 332/22, 332/23 R, 332/29 R, 455/46, 455/102, 455/108, 455/109
• US Class Current: 332/145
• CPC Class Codes: H03C 1/50 by converting angle modulation to amplitude modulation H03C1/28 - H03C1/34, H03C1/46, H03C1/48 take precedence
• CPC Class Codes: H03F 1/0294 using vector summing of two or more constant amplitude phase-modulated signals
• CPC Class Codes: H03F 1/3252 using multiple parallel paths between input and output H03F1/3258, H03F1/3282, H03F1/3294 take precedence

Abstract

An improved high efficiency amplitude modulation system comprising three power amplifier paths, each incorporating high efficiency type amplifiers.

One path amplifies an unmodulated carrier wave and the other two amplify phase modulated waves preferably generated by the disclosed improved Armstrong phase modulator.

Claims

1. The method of producing an envelope modulated wave by use of three signal amplifiers comprising the following steps:

(a) generating an unmodulated carrier wave,

(b) amplifying said unmodulated carrier wave in a first signal amplifier,

(c) phase modulating a portion of the carrier wave generated in step (a) with an input signal to produce a first phase modulated wave,

(d) amplifying said first phase modulated wave in a second signal amplifier,

(e) phase modulating another portion of the carrier wave generated in step (a) with the input signal to produce a second phase modulated wave,

(f) amplifying said second phase modulated wave in a third signal amplifier, and,

(g) combining the amplified waves resulting from steps (b), (d) and (f) to produce the desired envelope modulated wave.

2. The method of claim 1 wherein the carrier of the phase modulated wave amplified in step (d) is in quadrature with the unmodulated carrier wave amplified in step (b) and the carrier of the phase modulated wave amplified in step (f) is 180 degrees out-of-phase with the carrier of the phase modulated wave amplified in step (d).

3. The method of envelope modulating an angular modulated wave so as to produce a hybrid modulated wave comprising the following steps:

(a) amplifying said angular modulated wave in a first signal amplifier,

(b) phase modulating a portion of the angular modulated wave with an input signal to produce a first further modulated wave,

(c) amplifying said first further modulated wave in a second signal amplifier,

(d) phase modulating another portion of the angular modulated wave with the input signal to produce a second further modulated wave,

(e) amplifying said second further modulated wave in a third signal amplifier, and,

(f) combining the amplified waves resulting from steps (a), (c) and (e) to produce the desired hybrid modulated wave.

4. The method of claim 3 wherein the angular modulated wave is the angular modulation component of a Compatible SSB wave and said input signal is the envelope component of the Compatible SSB wave.

5. A device for producing envelope modulated waves the envelope being essentially a linear function of an input signal wave comprising;

means for generating an unmodulated carrier wave,

a first path for amplifying the unmodulated carrier wave,

means for generating a first phase modulated wave having a carrier component essentially in quadrature with the carrier wave amplified in the first path, and said phase modulation being a function of said input signal,

a second path for amplifying said first phase modulated wave,

means for generating a second phase modulated wave having a carrier component which is essentially 180 degrees out-of-phase with the carrier component of the first phase modulated wave and essentially the same function of said input signal wave, as the first phase modulated wave,

a third path for amplifying said second phase modulated wave, and,

means for combining the outputs of the three paths and feeding the resulting envelope modulated wave to an utilization device.

6. The device of claim 5 wherein at least one amplifier used in each of the three paths is a high efficiency type nonlinear amplifier.

7. The device of claim 5 wherein the means for generating the first and second phase modulated waves are Armstrong type modulators incorporating means for varying only the amplitude of the quadrature component wave so as to produce a phase modulation closely approximating an arc sine function of said input signal wave.

8. The device of claim 5 wherein the path amplifying the unmodulated wave produces, under 100% sinusoidal modulation conditions two-thirds of the output power and the total power from the two other paths produces the remaining one-third of the power.

9. An Armstrong type phase modulator wherein a double-sideband suppressed carrier wave is added to a quadrature carrier, comprising a carrier wave source, an input signal source, means for producing the double-sideband suppressed carrier signal from the carrier wave and the input signal, and means for causing the carrier to be in quadrature with the suppressed carrier wave, the improvement being providing means for reducing the amplitude of the quadrature carrier component as a function of the input signal so as to cause the resultant wave'"'"'s angular displacement from its unmodulated phase to approximate an arc sine function of said input signal.

10. The Armstrong modulator of claim 9 wherein the amplitude of the quadrature carrier is reduced from its unmodulated condition by a factor equal to:

##EQU2## where e(t) is a normalized function of said input signal.

11. The Armstrong modulator of claim 9 wherein the said means for reducing the amplitude of the quadrature carrier comprises;

(a) means for squaring the signal from said source of input signal audio wave which feeds,

(b) means for subtracting the output of the squaring means from a dc voltage which in turn feeds,

(c) means for square-rooting the output of the (b) subtraction circuit, and,

(d) means for causing the output of the square rooting circuit to reduce the amplitude of the quadrature carrier component.

12. The Armstrong modulator of claim 9 wherein the same means for reducing the amplitude of the quadrature carrier comprises;

(a) means for detecting the envelope amplitude of the combined quadrature carrier and the double-sideband suppressed carrier wave, and,

(b) means for using the detected envelope amplitude to control the gain of a circuit so as to reduce only the quadrature carrier wave'"'"'s amplitude as a function of (a) detection means.

13. An Armstrong type phase modulator comprising;

(a) means for producing a double-sideband suppressed carrier wave connected to an input signal source, and a carrier wave generator,

(b) phase shifting means so connected as to cause a carrier wave sample to be essentially in quadrature with the phasor sum of the components of the double-sideband suppressed carrier wave,

(c) means for controlling the amplitude of only said carrier wave sample as a function of said input signals so that the phasor sum of the controlled amplitude carrier wave and said double-sideband suppressed carrier wave has essentially a constant amplitude envelope, and

(d) means for combining the output of (a) means and the output of (c) means.

14. A device for producing envelope modulated waves comprising;

means for generating two angular modulated waves relatively free of envelope modulation the sum of said waves is essentially a double-sideband suppressed carrier wave with a single upper and lower sideband component for every input signal spectral component,

separate means for amplifying each of said two angular modulated waves,

means for amplifying an unmodulated wave that has a frequency equal to the arithmetic means of said double-sideband suppressed carrier wave, and,

means for combining the outputs of the three amplifying means to produce an envelope modulated wave.

15. An Armstrong type modulator suitable for use in hybrid modulation transmitters comprising;

(a) balanced modulator means whose signal port is connected to an input signal source and whose carrier port is connected to a source of angular modulated waves,

(b) means for shifting the relative phase of a sample of the angular modulated waves and the output of the balanced modulator means by 90 degrees,

(c) means for controlling the amplitude of the angular modulated wave sample as a function of the input signal so that the phasor sum of the quadrature related controlled amplitude angular modulated wave and the wave generated in said balanced modulator means has essentially a constant amplitude envelope, and,

(d) means for combining the resulting two quadrature related waves.

16. An Armstrong type phase modulator incorporating a nonlinear circuit, which, when fed by a modulating signal produces a wave which only controls the amplitude of a carrier or reference angular modulated wave so that the sum of the carrier or reference wave and a double-sideband suppressed carrier or reference wave, generated by a balanced modulator whose signal input port is also fed by said modulating signal and whose suppressed carrier or reference wave is in quadrature with the said first carrier or reference wave is a substantially constant amplitude wave,

said nonlinear circuit comprising a squaring means which squares the modulating signal voltage, a difference circuit connected to the output of the squaring means and which subtracts the output of the squaring means from a dc voltage, and a square root means which is connected to the output of the difference means.