speedy-33 maximum DSP capacity

[pagauthier]

Hello,

I am new to Labview and Speedy-33. We currently working on a small project using biquads on the Speedy-33. For the moment, it work perfectly. Ideally, I would need 48 biquads to implement stereo octave band filters. I think that the DSP capacity limit is more about ~18 biquads (with a sampling rate 36kHz), at least according to my experience. Using 18 biquads, I think that I get some glitch indicating the max DSP capacity?

Does 48 biquads seems impossible on a single Speedy?

What would indicate me that I am exeeding the DSP capacity at 36kHz? What is the biggest filtering operation we can imagine on a Speedy-33?

Also, what may reduce my capacity is that use a table to store my coefficient. Maybay the routing of this table (with supplementary "index array" to extract the proper coef) consume even more computing time?

Thank you,

[Eriquito]

Hi pagauthier,

Unfortunately, it is difficult to calculate the number of biquad stages that could be executed at 36 kHz on the SPEEDY-33 for a variety of reasons.  It doesn't surprise me, however, that the DSP is having trouble keeping up in real-time.

You could try using the DFD Filter Express VI (along with the Digital Filter Design Toolkit to design the filter) to design something that will have a better chance of running in real-time.