Adaptive digital correction of analog errors in MASH ADCs. II. Correction using test-signal injection

For pt. I see ibid., vol. 47, no. 7, p. 621-8 (2000). This part describes a different adaptation strategy. It relies on the injection of a pseudorandom two-level test signal at the input of the first-stage quantizer, where it is added to the quantization noise. The test signal then leaks into the output signal, where it can be detected and used to control the digital noise-cancellation filter. This paper describes the correction process, as well as some efficient structures for implementing it, and demonstrates the effectiveness of the technique by describing three design examples