A Successive Approximation Register, SAR, Analog to Digital Converter, ADC, (50) achieves high speed and accuracy by (1) alternating at least some decisions between sets of comparators having different accuracy and noise characteristics, and (2) unevenly allocating redundancy (in the form of LSBs of range) for successive decisions according to the accuracy/noise of the comparator used for the preceding decision. The redundancy allocation is compensated by the addition of decision cycles. Alternating between different comparators removes the comparator reset time (treset) from the critical path, at least for those decision cycles. The uneven allocation of redundancy—specifically, allocating more redundancy to decision cycles immediately following the use of a lower accuracy/higher noise comparators—compensates for the lower accuracy and prevents the need for larger redundancy (relative to the full-scale range of a decision cycle) later in the ADC process.

Described herein is a method and apparatus for enhancing the dynamic range of a digital-to-analog conversion circuit. Dynamic range enhancement (DRE) is accomplished by modifying the gain of components of the circuit so that the gain of components generating noise is effectively reduced. In a circuit utilizing a plurality of 1-bit DACs, analog signal gain is decreased when the full nominal gain of the analog portion of the circuit is not needed to obtain a desired peak output amplitude. The reduction is accomplished by effectively “disconnecting” some of the plurality of 1-bit DACs. Some or all of the 1-bit DACs are configured to have a third or “tri-state” in which there is no connection to the normal two reference levels thus providing no output. If some portion of the 1-bit DACs is placed in the tri-state, both the signal and noise gain will be reduced.

Embodiments disclosed herein may reduce or even eliminate spurs introduced into the signals during analog to digital or digital to analog conversions. The spurs may be introduced by components such as clocks of the converter circuits. In an analog to digital conversion, the input signal may be split into two parts: the first portion passing through a first analog to digital converter (ADC) and an inverted second portion passing through a second ADC. A digital subtractor may subtract the output of the second ADC from the output of the first ADC converter thereby reducing the spurs. In digital to analog conversion, a digital input is passed through a first digital to analog converter (DAC) and an inverted digital input is passed through a second DAC. The output of the second DAC is inverted and combined with the output of the first DAC to reduce the spurs.

An apparatus and method for carrier frequency estimation include a carrier frequency estimator having: a frequency input terminal disposed to receive a frequency-domain input signal comprising a plurality of symbols; a plurality of candidate pipelines, each comprising a frequency adder coupled to the frequency input terminal, a bit converter coupled to the frequency adder, a multi-bit buffer coupled to the bit converter; and a correlator coupled to the multi-bit buffer, respectively; and a candidate pipeline selector coupled to the correlators.

There is disclosed herein analogue-to-digital converter circuitry, comprising a set of sub-ADC units each for carrying out analogue-to-digital conversion operations, the set comprising a given number of core sub-ADC units for carrying out said given number of core conversion operations. Also provided is control circuitry operable, when a said sub-ADC unit is determined to be a defective sub-ADC unit, to cause the core conversion operations to be carried by the sub-ADC units of the set sub-ADC units other than the defective sub-ADC unit.

A Successive Approximation Register, SAR, Analog to Digital Converter, ADC, (50) achieves high speed and accuracy by (1) alternating at least some decisions between sets of comparators having different accuracy and noise characteristics, and (2) unevenly allocating redundancy (in the form of LSBs of range) for successive decisions according to the accuracy/noise of the comparator used for the preceding decision. The redundancy allocation is compensated by the addition of decision cycles. Alternating between different comparators removes the comparator reset time (treset) from the critical path, at least for those decision cycles. The uneven allocation of redundancy—specifically, allocating more redundancy to decision cycles immediately following the use of a lower accuracy/higher noise comparators—compensates for the lower accuracy and prevents the need for larger redundancy (relative to the full-scale range of a decision cycle) later in the ADC process.

A TI-ADC (50) comprising a group of sub-ADCs (A.sub.1-A.sub.M+N) is disclosed. During operation, M≥2 of the sub-ADCs (A.sub.1-A.sub.M+N) are simultaneously operated for converting M respective consecutive input signal samples of the TI-ADC (50) from an analog to a digital representation. The total number of sub-ADCs (A.sub.1-A.sub.M+N) in the group is M+N, N≥1. The TI-ADC (50) comprises error-estimation circuitry (60) for estimating errors of the sub-ADCs (A.sub.1-A.sub.M+N). Furthermore, the TI-ADC (50) comprises a control circuit (55) configured to, for each input signal sample, assign which sub-ADC (A.sub.1-A.sub.M+N) is to operate on that input signal sample. The control circuit (55) is configured to, for sub-ADCs (A.sub.k.sub.1) in a first subset of the group of sub-ADCs (A.sub.1-A.sub.M+N), which are subject to error estimation by the error-estimation circuitry (60), perform the assignment according to a first scheme. Moreover, the control N circuit (55) is configured to, for sub-ADCs (A.sub.k.sub.2) in a second subset of the group of sub-ADCs (A.sub.1-A.sub.M+N), which are not subject to error estimation by the error-estimation circuitry (60), perform the assignment according to a second scheme, different from the first scheme.

Systems and methods for processing and storing digital information are described. One embodiment includes a method for linearizing digital-to-analog conversion including: receiving an input digital signal; segmenting the input digital signal into several segments, each segment being thermometer-coded; generating a redundant representation of each of the several segments, defining several redundant segments; performing a redundancy mapping for the several segments, defining redundantly mapped segments; assigning a probabilistic assignment for redundantly mapped segments; converting each redundantly mapped segment into an analog signal by a sub-digital-to-analog converter (DAC); and combining the analog signals to define an output analog signal.

Systems and methods for processing and storing digital information are described. One embodiment includes a method for linearizing digital-to-analog conversion including: receiving an input digital signal; segmenting the input digital signal into several segments, each segment being thermometer-coded; generating a redundant representation of each of the several segments, defining several redundant segments; performing a redundancy mapping for the several segments, defining redundantly mapped segments; assigning a probabilistic assignment for redundantly mapped segments; converting each redundantly mapped segment into an analog signal by a sub-digital-to-analog converter (DAC); and combining the analog signals to define an output analog signal.

A TI-ADC (50) comprising a group of sub-ADCs (A.sub.1-A.sub.M+N) is disclosed. During operation, M≥2 of the sub-ADCs (A.sub.1-A.sub.M+N) are simultaneously operated for converting M respective consecutive input signal samples of the TI-ADC (50) from an analog to a digital representation. The total number of sub-ADCs (A.sub.1-A.sub.M+N) in the group is M+N, N≥1. The TI-ADC (50) comprises error-estimation circuitry (60) for estimating errors of the sub-ADCs (A.sub.1-A.sub.M+N). Furthermore, the TI-ADC (50) comprises a control circuit (55) configured to, for each input signal sample, assign which sub-ADC (A.sub.1-A.sub.M+N) is to operate on that input signal sample. The control circuit (55) is configured to, for sub-ADCs (A.sub.k.sub.1) in a first subset of the group of sub-ADCs (A.sub.1-A.sub.M+N), which are subject to error estimation by the error-estimation circuitry (60), perform the assignment according to a first scheme. Moreover, the control N circuit (55) is configured to, for sub-ADCs (A.sub.k.sub.2) in a second subset of the group of sub-ADCs (A.sub.1-A.sub.M+N), which are not subject to error estimation by the error-estimation circuitry (60), perform the assignment according to a second scheme, different from the first scheme.