System and method for spread spectrum ADC noise reduction

摘要

Methods, systems, and apparatuses, including electrical circuits, are described for spread spectrum ADC noise reduction. An analog-to-digital converter may include an analog modulator to modulate an input analog signal according to a pseudo-noise sequence. An ADC core may convert the modulated analog input signal to a digital signal representation thereof. The digital signal may be demodulated using the pseudo-noise sequence to generate a noise-spread signal with reduced noise spectral density. The analog modulator and digital demodulator may also be configured in an analog-to-digital converter that includes a comparator and successive approximation register (SAR) logic, rather than an ADC core, in a SAR implementation. Multi-lane, interleaved analog-to-digital conversion circuits are also described using the inventive techniques. Analog-to-digital converters including DC offset components and methods performed according to the inventive techniques are also described.

主权项

1. An analog-to-digital conversion circuit that comprises:
an analog modulator configured to receive and modulate an input analog signal according to a pseudo-noise (PN) sequence; an analog-to-digital converter (ADC) core that includes a first analog input, a second analog input, and a digital output, the ADC core being configured to differentially receive the modulated input analog signal on the first and second analog inputs, and to convert the modulated input analog signal to a digital signal generated on the digital output; and a digital demodulator configured to receive and demodulate the digital signal according to the PN sequence to generate a noise-spread signal; wherein at least one of: the analog modulator modulates the input analog signal based on a plurality of switches controlled by the PN sequence; or the analog-to-digital conversion circuit removes a direct current (DC) offset from the digital signal on the digital output.