Antialiasing And Sync-Compensation Filter


Posted on Oct 10, 2012

Two dual-biquad filter chips and some external components form a multipurpose filter to reconstru


Antialiasing And Sync-Compensation Filter
Click here to download the full size of the above Circuit.

ct D/A converter signals. Connected to a converter"s output, the filter provides antialiasing, reduces the D/A converter"s quantization noise, and compensates for sin(7rx)()—the "sync" function (attenuation). The circuit incorporates an inverse-sync function that operates to one-third of the converter"s sample rate. Beyond one-third, the filter"s response shifts to a stopband filter, which provides -70 dB attenuation. This attenuation conforms to the converter"s inherent signal-to-noise ratio and quantization error. To prevent aliasing, the stopband edge must be no higher than the Nyquist frequency (/„ + 2). To achieve 70-dB stopband rejection with this eighth-order filter requires a transition ratio (/stopband -K/passband) of 1.5, which sets the passband"s upper limit at fs +3. Notice also that you can apply a simple divide-by-64 circuit to the 192-kHz clock frequency to set the necessary 3 ratio between the converter"s sample rate and the filter"s 1-kHz corner frequency.




Leave Comment

characters left:

New Circuits

.

 


Popular Circuits

antenna tuner for better DX
Microphone FM bug transmitter
Rugged lamp driver
gps driven clock compasss peedo
Single Chip FM Transmitter Circuit
bugbot
bluetooth controlled relay
Multivibrator
Mains Slave Switcher
XTR101 thermocouple input circuit diagram
Sequential Actuator for powering up to four devices



Top