Large programmable delay at high frequency through aliasing

Abstract

A programmable alias delay device providing output in a desired frequency band and a maximum delay of >5 ns over a broad bandwidth and at a high frequency is disclosed. The device includes an input bandpass filter and an input stage with M sampling switched capacitor elements, reducing the sampling rate by M. The device includes a programmable delay stage with M programmable switched capacitor banks, each bank having N delay switched capacitor storage elements, reducing the sampling rate by M×N. This reduced sampling rate permits smaller sampling switches, with reduced leakage current and longer programmable delay times. The device includes an output reconstruction stage that reconstructs a delayed version of the input signal by combining signals from the programmable delay stage. Using a subsequent output alias filter, an alias band in the desired frequency band is selected and output.