Radio-frequency (RF) receivers having bandpass sigma-delta analog sigma analog-to-digital converters (ADC) designed to digitize signals in the RF domain are described. Such bandpass ADCs utilize one or more of the following techniques to enhance noise immunity and reduce power consumption: generation of in-phase (I) and quadrature (Q) paths in the digital domain, n.sup.th order resonant bandpass filtering with n>1, and signal sub-sampling in an i.sup.th Nyquist zone with i>1. Compared to RF receivers in which the I and Q paths are generated in the analog domain, these RF receivers exhibit higher IRRs because they are not susceptible to in-phase/quadrature (IQ) mismatch. Using n.sup.th order resonant bandpass filtering with n>1 attenuates unwanted image tones. The bandpass ADC-based RF receivers described herein exhibit enhanced immunity to noise, achieving for example image rejection ratios (IRR) in excess of 95 dB.

The disclosure provides a receiver with high dynamic range. The receiver includes a photodiode that generates a current signal. A coupling capacitor is coupled to the photodiode, and generates a modulation signal in response to the current signal received from the photodiode. A sigma delta analog to digital converter (ADC) is coupled to the coupling capacitor, and generates a digital data in response to the modulation signal. A digital mixer is coupled to the sigma delta ADC, and generates an in-phase component and a quadrature component corresponding to the digital data. A processor is coupled to the digital mixer, and processes the in-phase component and the quadrature component corresponding to the digital data.

An analog to digital conversion circuit includes an analog to digital converter (ADC) circuit operable to convert an analog signal having an oscillation frequency into a first digital signal having a first data rate frequency, where the analog signal includes a set of pure tone components. The analog to digital conversion circuit further includes a digital decimation filtering circuit operable to convert the first digital signal into a second digital signal having a second data rate frequency. The analog to digital conversion circuit further includes a digital bandpass filter (BPF) circuit operable to convert the second digital signal into an outbound digital signal having a third data rate frequency, where the digital bandpass filter circuit is set to produce a bandpass region approximately centered at the oscillation frequency of the analog signal and having a bandwidth tuned for filtering a pure tone.

A dynamic-zoom analog to digital converter (ADC) having a coarse flash ADC and a fine passive single-bit modulator is disclosed. Radio frequency (RF) devices incorporating aspects of the present disclosure may support multiple wireless modes operating at different frequencies. Therefore, the RF devices have need for an ADC which is flexible and optimizable in terms of resolution, bandwidth, and power consumption. In this regard, the RF devices incorporate circuits, such as ADC circuits, which incorporate a discrete-time passive delta-sigma modulator. In order to improve the resolution of the delta-sigma modulator, a coarse ADC is deployed as a zooming unit to a single-bit passive delta-sigma modulator to provide a coarse digital conversion. Coarse conversion is used to dynamically update reference voltages at an input of the delta-sigma modulator using a multi-bit feedback digital to analog converter (DAC). The dynamic-zoom ADC supports multiple modes with improved power and quantization noise.

A method for adjusting the resonance frequency of a loop filter in a delta-sigma modulator includes input of a filter input signal of a loop filter into a frequency adjustment circuit and determination of a noise spectrum of the filter input signal in a first frequency band and a second frequency band. The first frequency band and the second frequency band are arranged symmetrically around the predetermined frequency. The method includes comparison of the noise spectra and creation of an adjustment signal that leads to a frequency adjustment when the noise spectra deviate from one another. The method also includes feedback of the adjustment signal of the frequency adjustment circuit to a control input of the loop filter for setting the filter frequency in response to the comparative result.

A Sigma-Delta () modulator for converting an analog input signal having a frequency bandwidth around a variable center frequency f.sub.0 to a digital output signal at a sampling frequency f.sub.s. The modulator comprises a quantizer (420) for generating the digital output signal and a loop filter for shaping the quantization noise. The loop filter comprises at least one subfilter (430, 410) centered around a frequency f.sub.0 and constant noise shaping coefficients (451, 452, 453). The modulator further comprises a tunable delay element (455), a frequency adjuster (480) for adjusting the sampling frequency f.sub.s such that the normalized center frequency f.sub.0/f.sub.s is constant, and a delay adjuster (490) for adjusting the loop delay t.sub.d implemented by the quantizer and the tunable delay element (455), such that the normalized loop delay t.sub.d/T.sub.s falls in a predetermined range [t.sub.min, t.sub.max], where T.sub.s=1/f.sub.s.

A confined data communication system includes a reference generation circuit operable to produce one or more analog reference signals, an analog to digital converter circuit operable to process an analog signal to produce a digital representative signal, a digital filtering circuit operable to filter the digital representative signal to produce an affect value, a data processing module operable to interpret the affect value to produce processed output data, and a processing module operable to set frequency and waveform for each of the one or more analog reference signals, set digital filtering parameters for the digital filtering circuit, set a sampling rate for the analog to digital converter circuit, and set data interpretation parameters for the data processing module.

A method for extended-pulse sampling includes providing a continuous-time signal comprising a frequency spectrum within a predetermined passband. The continuous time signal is sampled with a plurality of discrete sample pulses having a pulse shape in a time domain that is an impulse response of a filter having the predetermined passband. The plurality of discrete time samples of the continuous-time signal is then provided to an output.

A baseband processing unit includes a baseband processor configured to receive a plurality of component carriers of a radio access technology wireless service, and a delta-sigma digitization interface configured to digitize at least one carrier signal of the plurality of component carriers into a digitized bit stream, for transport over a transport medium, by (i) oversampling the at least one carrier signal, (ii) quantizing the oversampled carrier signal into the digitized bit stream using two or fewer quantization bits.

A dynamic-zoom analog to digital converter (ADC) having a coarse flash ADC and a fine passive single-bit modulator is disclosed. Radio frequency (RF) devices incorporating aspects of the present disclosure may support multiple wireless modes operating at different frequencies. Therefore, the RF devices have need for an ADC which is flexible and optimizable in terms of resolution, bandwidth, and power consumption. In this regard, the RF devices incorporate circuits, such as ADC circuits, which incorporate a discrete-time passive delta-sigma modulator. In order to improve the resolution of the delta-sigma modulator, a coarse ADC is deployed as a zooming unit to a single-bit passive delta-sigma modulator to provide a coarse digital conversion. Coarse conversion is used to dynamically update reference voltages at an input of the delta-sigma modulator using a multi-bit feedback digital to analog converter (DAC). The dynamic-zoom ADC supports multiple modes with improved power and quantization noise.