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ADAU1452 crossover design sample rate problems

Question asked by jrosser on Dec 11, 2015
Latest reply on Apr 1, 2016 by TylerK

In a simple ADAU1452 design (SigmaStudio 3.12):

 

44.1kHz SPDIF input, ASRC, 2 way crossover, I2S out to DACs

 

Everything works reasonably at 48kHz. If I change the sample rate of the design to 192kHz then the crossover point moves significantly, completely obvious just by listening to one of the HF or LF outputs.

 

In addition, the graph plotted by the crossover block does not rescale to represent the new sample rate, remaining with a max of 22kHz.

 

So a couple of things:

 

Is it right that in a 48kHz design the graph in the crossover block only goes up to 22kHz, suggesting an assumption of 44.1kHz?

 

Why does the actual crossover point seem to change as a function of the design sample rate, when it should follow what is specified in the crossover block regardless of Fs?

 

Is this a bug? Do I need to do anything to change Fs other than propagate the new sample rate across the design and recompile/link/download?

 

Jonathan.

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