Conversion of analogue values to or from differential modulation

HELECTRICITY H03Electronic circuits H03MCODING DECODING CODE CONVERSION IN GENERAL

H03M3/00Conversion of analogue values to or from differential modulation

H03M3/02Delta modulation H03M3/022with adaptable step size H03M3/024using syllabic companding H03M3/04Differential modulation with several bits H03M3/042with adaptable step size H03M3/30Delta-sigma modulation H03M3/32with special provisions or arrangements for power saving H03M3/322Continuously compensating for, or preventing, undesired influence of physical parameters H03M3/324characterised by means or methods for compensating or preventing more than one type of error at a time H03M3/326by averaging out the errors H03M3/328using dither H03M3/33the dither being a random signal H03M3/332in particular a pseudo-random signal H03M3/334the dither being at least partially dependent on the input signal H03M3/336the dither being in the time domain H03M3/338by permutation in the time domain H03M3/34by chopping H03M3/342by double sampling H03M3/344by filtering other than the noise-shaping inherent to delta-sigma modulators H03M3/346by suppressing active signals at predetermined times H03M3/348using return-to-zero signals H03M3/35using redundancy H03M3/352of deviations from the desired transfer characteristic H03M3/354at one point, i.e. by adjusting a single reference value H03M3/356Offset or drift compensation H03M3/358of non-linear distortion H03M3/36by temporarily adapting the operation upon detection of instability conditions H03M3/362in feedback mode H03M3/364by resetting one or more loop filter stages H03M3/366in feed-forward mode H03M3/368of noise other than the quantisation noise already being shaped inherently by delta-sigma modulators H03M3/37Compensation or reduction of delay or phase error H03M3/372Jitter reduction H03M3/374Relaxation of settling time constraints H03M3/376Prevention or reduction of switching transients H03M3/378Testing H03M3/38Calibration H03M3/382at one point of the transfer characteristic, i.e. by adjusting a single reference value H03M3/384Offset correction H03M3/386over the full range of the converter H03M3/388by storing corrected or correction values in one or more digital look-up tables H03M3/39Structural details of delta-sigma modulators H03M3/392Arrangements for selecting among plural operation modes H03M3/394among different orders of the loop filter H03M3/396among different frequency bands H03M3/398among different converter types H03M3/40Arrangements for handling quadrature signals H03M3/402Arrangements specific to bandpass modulators H03M3/404characterised by the type of bandpass filters used H03M3/406by the use of a pair of integrators forming a closed loop H03M3/408by the use of an LC circuit H03M3/41combined with modulation to or demodulation from the carrier H03M3/412characterised by the number of quantisers and their type and resolution H03M3/414having multiple quantisers arranged in cascaded loops, each of the second and further loops processing the quantisation error of the loop preceding it H03M3/416all these quantisers being multiple bit quantisers H03M3/418all these quantisers being single bit quantisers H03M3/42having multiple quantisers arranged in parallel loops H03M3/422having one quantiser only H03M3/424the quantiser being a multiple bit one H03M3/426the quantiser being a successive approximation type analogue/digital converter H03M3/428with lower resolution H03M3/43the quantiser being a single bit one H03M3/432the quantiser being a pulse width modulation type analogue/digital converter H03M3/434with multi-level feedback H03M3/436characterised by the order of the loop filter H03M3/438the modulator having a higher order loop filter in the feedforward path H03M3/44with provisions for rendering the modulator inherently stable H03M3/442by restricting the swing within the loop H03M3/444using non-linear elements H03M3/446by a particular choice of poles or zeroes in the z-plane, e.g. by positioning zeroes outside the unit circle H03M3/448by removing part of the zeroes H03M3/45with distributed feedforward inputs H03M3/452with weighted feedforward summation H03M3/454with distributed feedback H03M3/456the modulator having a first order loop filter in the feedforward path H03M3/458Analogue/digital converters using delta-sigma modulation as an intermediate step H03M3/46using a combination of at least one delta-sigma modulator in series with at least one analogue/digital converter of a different type H03M3/462Details relating to the decimation process H03M3/464Details of the digital/analogue conversion in the feedback path H03M3/466Multiplexed conversion systems H03M3/468Interleaved, i.e. using multiple converters or converter parts for one channel H03M3/47using time-division multiplexing H03M3/472Shared H03M3/474using time-division multiplexing H03M3/476Non-linear conversion systems H03M3/478Means for controlling the correspondence between the range of the input signal and the range of signals the converter can handle; Means for out-of-range indication H03M3/48characterised by the type of range control H03M3/482by adapting the quantisation step size H03M3/484by adapting the gain of the feedback signal H03M3/486by adapting the input gain H03M3/488using automatic control H03M3/49in feedback mode H03M3/492in feed forward mode H03M3/494Sampling or signal conditioning arrangements specially adapted for delta-sigma type analogue/digital conversion systems H03M3/496Details of sampling arrangements or methods H03M3/498Variable sample rate H03M3/50Digital/analogue converters using delta-sigma modulation as an intermediate step H03M3/502Details of the final digital/analogue conversion following the digital delta-sigma modulation H03M3/504the final digital/analogue converter being constituted by a finite impulse response [FIR] filter H03M3/506the final digital/analogue converter being constituted by a pulse width modulator H03M3/508Details relating to the interpolation process H03M3/51Automatic control for modifying converter range