Duty-cycle adjustable clock generator with low reverse bias and zero DC level
AssigneeRemec, Inc.
InventorShihchang Wu
Life of this patent
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Abstract
A duty-cycle adjustable clock generator is disclosed. Combining a fundamental sinusoidal waveform with its phase-locked second harmonic waveform generates the duty-cycle adjustable clock waveform. The clock generator maintains zero DC level and minimum reverse bias voltage swing at high microwave and millimeter wave frequencies. Proper phase shift between the fundamental and second harmonic waveforms produces the desired clock waveform. The duty-cycle is controlled by the magnitude ratio of the fundamental and phase-locked second harmonic waveforms. Due to the resulting zero DC level and minimum reverse bias voltage over the duty-cycle adjustable range, the duty-cycle adjustable clock generator can be effectively used in various microwave and optical communication systems.
Claims30
A clock generator, comprising:
- a first waveform generator for generating a first sinusoidal waveform having a desired clock frequency;
- a second waveform generator phase-locked to said first waveform generator for generating a second sinusoidal waveform having a frequency double that of said desired clock frequency;
- and
- a combiner for combining said first and second sinusoidal waveforms to produce a clock signal having said desired clock frequency.
An arrangement for sampling data with an adjustable sampling aperture, comprising:
- a sampler connected to receive input data and sample said input data to produce output data;
- and
- a clock circuit having a first waveform generator for generating a first sinusoidal waveform having a desired clock frequency, a second waveform generator phase-locked to said first waveform generator for generating a second sinusoidal waveform having a frequency double that of said desired clock frequency and a combiner for combining said first and second sinusoidal waveforms to produce a clock signal having said desired clock frequency;
- wherein said clock signal controls the sampling aperture of said sampler.
An NRZ-to-RZ converter with adjustable duty-cycle control, comprising:
- an optical modulator connected to receive an NRZ modulated waveform and output an RZ modulated waveform;
- and
- a clock circuit having a first waveform generator for generating a first sinusoidal waveform having a desired clock frequency, a second waveform generator phase-locked to said first waveform generator for generating a second sinusoidal waveform having a frequency double that of said desired clock frequency and a combiner for combining said first and second sinusoidal waveforms to produce a clock signal having said desired clock frequency;
- wherein the output of said clock circuit is connected to the electrical input of said optical modulator;
- wherein the duty-cycle of the RZ modulated signal output from said optical modulator is controllable via the duty-cycle of said clock circuit.
An optical-time-domain-multiplexing system, comprising:
- at least two NRZ-to-RZ optical modulators, each being connected to receive a respective NRZ optical modulated signal modulated using the same NRZ data input and convert said respective NRZ optical modulated signal to a respective RZ or NRZ optical modulated signal with a specific duty-cycle;
- an optical combiner connected to receive each said respective RZ or NRZ optical modulated signal and optically couple said received RZ or NRZ optical modulated signals into an output optical data stream;
- and
- a clock circuit having a first waveform generator for generating a first sinusoidal waveform having a desired clock frequency, a second waveform generator phase-locked to said first waveform generator for generating a second sinusoidal waveform having a frequency double that of said desired clock frequency and a combiner for combining said first and second sinusoidal waveforms to produce a clock signal having said desired clock frequency, said clock signal controlling said at least two NRZ-toRZ optical modulators;
- wherein the duty-cycle of said at least two NRZ-to-RZ optical modulators is controlled by the duty-cycle of said clock signal.
A method for generating a clock signal having a desired clock frequency, comprising:
- generating a first sinusoidal waveform having the desired clock frequency;
- generating a phase-locked second sinusoidal waveform having a frequency double that of said desired clock frequency;
- and
- combining said first and second sinusoidal waveforms to produce said clock signal having the desired clock frequency.
Dependencies are inferred from the claim text.