Analog / digital filtering

After the anti-aliasing filter, the analog/digital converter (ADC) quantizes the continuous input into discrete levels. ADC technology has shown considerable improvement in recent years due to the development of oversampling and noise-shaping converters. However, a look at the previous technologies [Blesser, 1978] [Blesser and Kates, 1978][Fielder, 1989] will help appreciate the current state-of-the-art. 

Recursive filter — A sort of - analog filter or - digital filter based on employing feedback to determine the current filtered output. In digital filters, the software technique is based on calculating the current filtered output (yn) from input values (x ,xn-, x -2,...) and previous filtered outputs (y -, y -2,...). Thus, previously calculated output values go back into the calculation of the... 

Signal filtering — A process used to eliminate unwanted frequencies, generated by electronic devices during the detection procedure, from a measured signal. Different analog filters and digital filters have been developed... 

Wu Y, et al. 1992. The design and analysis of an imp roved high air flow meter with analog/digital filters. IEEE Transactions on Instrumentation cuid Measurement, 41(6) 791 796. 

Yin L, Yang R, Gabbouj M, Neuvo Y. Weighted median filters a tutorial. IEEE Trans Circuit Syst II Analog Digit Signal Process. 1996 43(3) 157-92. 

Figure 17.6 A comparison of filter performance for additive sinusoidal noise (a) square-wave plus noise (b) analog exponential filters (c) digital exponential filters (d) moving-average filters.

Are there any circuits that are particularly noise-sensitive These include analog-to-digital and digital-to-analog converters, video monitors, etc. This may dictate that the supply has additional filtering or may need to be synchronized to the sensitive circuit. 

Fig. 1 Scheme of the OCT system. SLD—superluminescent diode FBS—fiber-optic beam splitter M—mirror L—lenses S—sample PD—photo-diode F—band-pass filter A— logarithmic amplifier AD—amplitude detector ADC—analog-to-digital converter PC— computer. 

Figure 7.3. Block diagram of a near-lR optical fiber deleclor. A/D = analog-to-digital A OIF = acoustic Optical tunable filter.

---