Async. scan rate converter - has interpolation filter increasing input scan rate and decimation filter reducing scan rate read out from holder

摘要

The test rate or sampling frequency converter has an interpolation filter (L1), by means of which the input test rate (fA1) of the input signal is enhanced by a factor (L1), followed by a holding unit (SH), from which the signal test values are read with a testing rate of (L2.fA2). Finally, a decimalisation filter reduces this testing rate by a factor (L2) to an output rate (fA2). The ratio of the input and output rates is not a rational number. Between the interpolation filter and the first holding unit, a first filter (H1) (z2) is inserted. The signal from this unit is fed through a second filter (H2) (z2) to a second holding unit (SH2), its output being fed back to the first holding unit (SH) through a subtracting unit (S) as a difference from its input signal. USE/ADVANTAGE - Increase in testing rate can be quite small, without errors arising and without undue costs. Suitable for audio industry, e.g. digital sampling frequency converter for digital audio.