Multi-mode sampling/quantization converters
AssigneeSyntropy Systems, LLC
InventorChristopher Pagnanelli
Life of this patent
Estimating the term…
Abstract
Provided are, among other things, systems, methods and techniques for converting a continuous-time, continuously variable signal into a sampled and quantized signal. According to one implementation, an apparatus includes multiple processing branches, each including: a bandpass noise-shaping circuit, a sampling/quantization circuit, and a digital bandpass filter. A combining circuit then combines signals at the processing branch outputs into a final output signal. The bandpass noise-shaping circuits include adjustable circuit components for changing their quantization-noise frequency-response minimum, and the digital bandpass filters include adjustable parameters for changing their frequency passbands.
Claims23
An apparatus for converting a continuous-time, continuously variable signal into a sampled and quantized signal, comprising:
- an input line for accepting an input signal that is continuous in time and continuously variable;
- a plurality of processing branches having inputs coupled to the input line, each of said processing branches including:
- (a) a bandpass noise-shaping circuit, (b) a sampling/quantization circuit coupled to an output of the bandpass noise-shaping circuit, and (c) a digital bandpass filter coupled to an output of the sampling/quantization circuit;
- and
- a combining circuit, coupled to outputs of a plurality of said processing branches, that combines signals on said outputs into a final output signal,
- wherein each of said digital bandpass filters includes:
- (a) a quadrature frequency downconverter, which uses discrete-time cosine and sine sequences to generate in-phase and quadrature outputs at baseband, (b) a first lowpass filter coupled to the in-phase output of the quadrature frequency downconverter, (c) a second lowpass filter coupled to the quadrature output of the quadrature frequency downconverter, and (d) a quadrature frequency upconverter coupled to outputs of the first and second moving-average filters, which uses discrete-time cosine and sine sequences to convert in-phase and quadrature inputs to a higher frequency output,
- wherein a center frequency of the digital bandpass filter in each said processing branch corresponds to a stopband region in a quantization noise transfer function for the bandpass noise-shaping circuit in the same processing branch,
- wherein the frequency response of each of said first and second lowpass filters has a magnitude that varies approximately with frequency according to the product of raised sin(x)/x functions, and
- wherein each of a plurality of said processing branches includes at least one adjustable parameter which, when adjusted, changes at least one of:
- (i) a frequency of at least one of the cosine or sine sequences, or (ii) a bandwidth of at least one of the first lowpass filter or the second lowpass filter.
Dependencies are inferred from the claim text.