Townshend Computer Tools DAT-Link - Stopband Attenuation

74 Sampling Rate Conversion
-120
-100
-80
-60
-40
-20
0
20
0
500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Frequency (Hz)
Magnitude (dB)
Figure 7.1: Measured Response Obtained with User-Specied Filter
7.3 Stopband Attenuation
Independently of whether the filter option is used, the default stopband attenu-
ation of 90 dB can also b e changed in the .datlinkrc le, as in:
*filter.stopband.atten: 60
This particular line was used for some of the example conversion sp ecications that
were shown in Table 7.1. As can b e seen from the table, smaller values result in lower
computational burden and, ultimately, sharper lters. Increasing the attenuation
muchabove90dBmay result in the software b eing unable to design a lter that
meets the requested sp ecications.