US 4,397,039 A · Instantaneous phase tracking in single sideband systems

Abstract

A receiver for demodulating a single sideband signal which is subject to rapid phase jitter employs a Hilbert splitter for obtaining the Hilbert transform of the single sideband signal, and a local oscillator for signal demodulation. A post-oscillator feedback loop instantaneously derives the amount of phase jitter in the single sideband signal, and employs the derived phase jitter to adjust the phase of the local oscillator so that the local oscillator tracks the single sideband signal. Instantaneous derivation of the phase jitter is obtained because all post-oscillator signal manipulations are algebraic; post-oscillator Hilbert transform generation is not required. A first embodiment derives the exact amount of phase jitter. A second embodiment, more simple than the first, derives the approximate amount of phase jitter.

Claims28

Dependent claims

Apparatus for receiving a single sideband input wave, the phase of which is subject to rapid jitter, comprising:

first means, connected to said single sideband input wave for generating a delayed replica of said single sideband input wave further subject to rapid phase jitter;
and
second means, connected to said first means, for deriving the amount of phase jitter present in said delayed replica of said single sideband input wave, said second means including demodulation and detection means to provide in-phase and quadrature phase single sideband components and a detected baseband data waveform and combining means for algebraically combining said in-phase demodulated component, said quadrature phase demodulated component, and said baseband data waveform, to obtain said phase jitter amount, said second means further cancelling the derived phase jitter from said delayed replica of said single sideband input wave without further delay with respect to said delayed replica of said single sideband input wave.

Apparatus for receiving a single sideband input wave, the phase of which is subject to rapid jitter, comprising:

Hilbert transform generating means connected to said single sideband input wave for generating the Hilbert transform of said single sideband input wave and a delayed replica of said single sideband input wave, with no delay between the delayed replica of the single sideband input wave and the Hilbert transform of the single sideband input wave;
demodulating means connected to said Hilbert transform generating means, for generating an in-phase demodulated component, a quadrature demodulated component, and a baseband data waveform from the Hilbert transform of said single sideband input wave and the delayed replica of said single sideband input wave, without further delay with respect to the delayed replica of said single sideband input wave;
combining means, connected to said demodulating means, for deriving the amount of phase jitter present in the delayed replica of said single sideband input wave, by combining said in-phase demodulated component, said quadrature demodulated component, and said baseband data waveform, the amount of phase jitter being derived without further delay with respect to said in-phase demodulated component, said quadrature demodulated component, said baseband data waveform;
and
feedback means connected to said combining means and said demodulating means, for cancelling the derived phase jitter from said in-phase demodulated component, said quadrature demodulated component and said baseband data waveform.

2 more elements

Apparatus for receiving a single sideband input wave, the phase of which is subject to rapid jitter, comprising:

Hilbert transform generating means connected to said single sideband input wave for generating the Hilbert transform of said single sideband input wave and a delayed replica of said single sideband input wave, with no delay between the delayed replica of the single sideband input wave and the Hilbert transform of the single sideband input wave;
a local oscillator for generating a local oscillator wave, the phase of said local oscillator wave being adjustable;
demodulating means connected to said Hilbert transform generating means and said local oscillator, for generating an in-phase demodulated component, a quadrature demodulated component, and a baseband data waveform from the Hilbert transform of said single sideband input wave and the delayed replica of said single sideband input wave, without delay with respect to said local oscillator wave, by combining the delayed replica of said single sideband input wave with the Hilbert transform of said single sideband wave and said local oscillator wave;
and
combining means, connected to said demodulating means, for sending a phase error signal to said local oscillator, said phase error signal representing the amount of phase jitter present in said single sideband input wave and being generated without delay with respect to said local oscillator wave by combining said in-phase demodulated component, said quadrature demodulated component and said baseband data waveform;
whereby the phase of said local oscillator wave is rapidly adjusted to track the phase jitter in said single sideband input wave.

3 more elements

Apparatus for receiving a single sideband input wave, the phase of which is subject to rapid jitter, comprising:

a Hilbert splitter connected to said single sideband input wave, for generating the Hilbert transform of said single sideband input wave and a delayed replica of said single sideband input wave, said Hilbert transform and said delayed replica being generated in synchronization with one another,
a local oscillator for generating local oscillator waves including an in-phase local oscillator wave and a quadrature local oscillator wave, the phase of said local oscillator waves being adjustable;
demodulating means, connected to said Hilbert splitter and said local oscillator, for generating an in-phase demodulated component, a quadrature demodulated component and a baseband data waveform from said delayed replica of said single sideband input wave, without delay with respect to said local oscillator waves by combining said local oscillator waves, said delayed replica of said single sideband input wave and said Hilbert transform;
and
combining means, connected to said demodulating means, for sending a phase error signal to said local oscillator, said phase error signal representing the amount of phase jitter present in said delayed replica of said single sideband input wave and being generated without delay with respect to said local oscillator waves by combining said in-phase demodulated component, said quadrature demodulated component and said baseband data waveform;
whereby the phases of said local oscillator waves are rapidly adjusted to track the phase jitter in said single sideband input wave.

3 more elements

Dependencies are inferred from the claim text.

Instantaneous phase tracking in single sideband systems

Life of this patent

Instantaneous phase tracking in single sideband systems

Life of this patent

Abstract

Claims28