C5535 Muxing and Combining Audio Channels

You might want to post to other DSP forum?

We've done a 6 in to 2 out mixer/switch on a 5000 dsp for an interior cabin communication system operating on voice signals, this is kind of a special case of a mixer.

A more generalized case is to define a N x C mixing matrix M, where N is number of inputs and C is number of output channels.  Then at time k, given a [1 x N] input vector XIN of the N inputs, use the mixing matrix to create the [1 x C] vector of outputs, YOUT

YOUT(k) = XIN(k) * M

where * implies a matrix multiplication.

That's the general concept. For example to mix 4 inputs to a stereo output, with say the 3rd input channel muted on the LEFT, the mixing matrix would look like:

| 1  1 |

| 1  1 |

| 0  1 |

| 1  1 |

So the implementation in a general sense is a matrix multiply operation. (note the above example doesn't take in consideration scaling to prevent overflow)

-S