An A/D converter includes a noise detector for generating a noise detection signal when it detects noise in an A/D conversion reference voltage; an A/D operation controller for generating a bit-shift signal in response to the noise detection signal; and an A/D conversion module for discarding an A/D conversion resultant bit affected by noise in response to the bit-shift signal, for holding the remaining A/D conversion resultant bits, and for restarting the A/D conversion from the discarded A/D conversion resultant bit after the noise becomes negligible. The A/D converter can obtain reliable A/D conversion data against the noise in the A/D conversion reference voltage without increasing the circuit scale so much.

A system for reducing noise coupling in a mixed-signal IC includes a digital clock, an analog clock, and gating signal generator, and a gating circuit. The gating circuit receives a digital clock signal and the gating pulse to generate a gated digital clock signal having no pulses at a sampling edge of the analog clock signal to provide a "quiet time" for analog sampling.

A time domain data converter with output frequency domain conversion. A data conversion circuit is operable to receive a signal in the time domain and provide an output in the frequency domain. It includes a data converter for converting data from an analog format to a digital format in the time domain. It also includes a processor for processing the data in the digital format output from the data converter through a time domain/frequency domain transform to provide data in the digital format in the frequency domain. The output of the frequency domain operation or the time domain operation can be provided for output in response to the generation of a data ready signal.

A method for suppressing interference in an integrated communication/computing device is disclosed. First, an interrupt signal is sent from a transceiver to a computing device when the transceiver is about to transmit or receive information. In response to the interrupt signal, the computing device stacks current status and enters an interrupt routine. The computing device is then released from the interrupt routine after the information has been transmitted or received.

A technique for separating an operation of a digital stage into separate noise generation periods in order to time the generation of noise from the digital stage. The invention is utilized in a mixed-signal integrated circuit having analog and digital signals in which the timing of the noise generation ensures that noise is abated during an analog sampling event.