Telefonaktiebolaget Lm Ericsson (publ)

Helge Stenstrom

Svante Signell

Bengt Erik Jonsson

Nianxiong Tan

Pipeline A/D-conversion of an analog input signal is performed according to a new and inventive algorithm which generates a Gray coded digital output signal. A pipeline A/D-converter comprises a number of cascaded stages through which the analog input signal is propagated. Each stage generally generates an output bit of the digital output signal, and furthermore processes the pipeline signal. According to the inventive Gray coding algorithm, the output bit generated in a stage determines whether or not the pipeline signal of that stage is inverted. In a pipeline A/D-converter based on the Gray coding algorithm according to the invention, the accumulation of offset errors will generally be very low. Furthermore, the fact that the signal inversion is digitally controlled enables high precision implementations which further improve the performance of the inventive pipeline A/D-converter. In another embodiment of the invention, the Gray coding algorithm is modified to form a second algorithm which makes low device count implementations possible.

Pipeline analog-to-digital conversion that reduces the accumulation

Cyclic A/D-conversion of an analog input signal is performed according to a new and inventive recursive algorithm which generates a Gray coded digital output signal. In cyclic A/D-conversion, the output bits are generated cyclically, one by one. According to the inventive Gray coding algorithm, the analog input signal is cyclically subjected to a sample and hold operation, selectively, depending on the previously generated output bit, to a signal inversion, to an amplification by two, and to an addition of a predetermined reference signal. In a cyclic A/D-converter architecture based on the recursive Gray coding algorithm according to the invention, the accumulation of offset errors will generally be very low. Furthermore, the fact that the signal inversion is digitally controlled enables high precision implementations which further improve the performance of the cyclic A/D-converter according to the invention.

Growing community of inventors

Stockholm, Sweden

Helge Stenstrom