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ADAU1787 - Import/generate custom FIR filter coefficients

Quick questions before learning a new tool and starting development with ADAU1787 eval board using Sigma Studio (never used this tool before).

I want to set up a 1-channel mono (microphone) - input, and 2 channel quadrature output (for a radio communication product development). The frequency range of the mono-input (and output) is voice band: 300 Hz - 3600Hz. 

The 2-channel output audio signal (quadrature I&Q) will be achieved by loading Hilbert FIR filter coefficients externally on boot; unique set of coefficients for the I and Q channels respectively.

I assume a Hilbert transform is not available in Sigma Studio. I can generate my own Hilbert transform coefficients (not Matlab).

1. Assuming this is doable but would appreciate someone directing me to the appropriate tools inside Sigma Studio to allow file imports.

2. Alternatively, can C-scripts be used inside Sigma studio to generate the coefficients upon boot?

I would appreciate some advice before diving in.

Please advise. Thank you


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  • Hi Dave, thanks for your follow-up.  The Hilbert will work. Now to zero in on what device best fits.  My criteria: cost and availability.

    I initially picked the ADAU1787 due to it high sampling rate (768k).   However, min 384 k is fine.

    To better define the application: This will be a baseband audio simplex (either in receiver or transmit) processor: 

    Receive: An input signal from the RF receiver is baseband- sampled, an FFT performed by the DUT with FFT data (bin magnitude) moved over a serial port to a micro-controller-TFT display. Simultaneously, a signal of interest (3.6 kHz max bw) inside that spectrum will be processed through the Hilbert to obtain I and Q -( 90 deg quadrature). I and Q are then combined (either added or subtracted) to obtain audio.

    Transit (receive disabled): microphone or line mono-audio-input is Hilbert transformed with the 2 channels used to drive an external I-Q modulator.

    Please advise candidate ADAUxxx devices.

    Thanks again, Don

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