Direct digital frequency synthesizer using sigma-delta technique

Details Direct digital frequency synthesizer using sigma-delta technique Direct digital frequency synthesizer using sigma-delta technique

1994-11-29

1996-10-08

Callahan, Timothy P.

Miscellaneous active electrical nonlinear devices, circuits, and

Signal converting, shaping, or generating

Synthesizer

327106, 327159, 331 1A, 331 16, 331 25, 341118, 341143, H03B 2100

Patent

active

055635350

ABSTRACT:
A direct digital synthesizer (DDS) for generating a waveform generates a sequence of n-bit phase signals representing phase of the waveform, wherein n is an integer greater than zero. Each n-bit phase signal comprises a phase estimate signal and a phase error signal. The phase estimate signal comprises a most-significant m bits of the n-bit quantity (0 <m<n). The phase-error signal comprises a least-significant n-m bits of the n-bit quantity. The DDS further has a sigma-delta modulator for generating a compensation signal from the phase error signals. The phase estimate signal is added to the compensation signal to produce a compensated phase signal, which may be used to address a look-up table having waveform samples stored in correspondence with look-up table addresses. A digital to analog converter may be coupled to receive waveform samples from the look-up table in order to generate a corresponding analog waveform signal. In accordance with another aspect of the invention, an improved modulator includes the improved DDS as described above, for generating a stream of carrier signal samples; and a complex multiplier/accumulator (CMAC) for multiplying a stream of the carrier signal samples by a stream of complex data values that represent a baseband signal. The output of the CMAC is a stream of modulated carrier signal samples that may be supplied to a digital to analog converter which generates a corresponding analog modulated carrier signal.

REFERENCES:
patent: 3654450 (1972-04-01), Webb
patent: 4454486 (1984-06-01), Hassun et al.
patent: 4772871 (1988-09-01), Suzuki et al.
patent: 4857928 (1989-08-01), Gailus et al.
patent: 4972360 (1990-11-01), Cuckler et al.
patent: 4999625 (1991-03-01), Thompson
patent: 5038117 (1991-08-01), Miller
patent: 5055802 (1991-10-01), Hietala et al.
patent: 5084702 (1992-01-01), Ribner
patent: 5164727 (1992-11-01), Zakhor et al.
patent: 5181032 (1993-01-01), Ribner
patent: 5220326 (1993-06-01), Ledzius et al.
patent: 5225787 (1993-07-01), Therssen
patent: 5243344 (1993-09-01), Koulopoulos et al.
patent: 5243345 (1993-09-01), Naus et al.
patent: 5245344 (1993-09-01), Sooch
patent: 5305004 (1994-04-01), Fattaruso
patent: 5311181 (1994-05-01), Ferguson, Jr. et al.
patent: 5313205 (1994-05-01), Wilson
P. O'Leary and F. Maloberti, "A Direct-Digital Synthesizer with Improved Spectral Performance", IEEE Transactions on Communications vol. 39, No. 7, pp. 1046-1048 (Jul. 1991).
P. O'Leary et al., "Oversampling Data Conversion Applied to Data Modulation", International Conference on Analog to Digital and Digital to Analogue Conversion, pp. 124-129, 17-19 Sep. 1991 (Swansea UK, IEE London, UK 1991).
B. Miller, "Technique Enhances the Performance of PLL Synthesizers," Microwaves & RF pp. 59-65 (Jan. 1993).

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