[sdiy] Attenuation in Digi-land

[Veronica Merryfield]

Whilst you could use bit shift, you will be limited to attenuation of 1/2, 1/4, 1/8, 1/16 and so on (1/2^n). You might find this too limiting. 

However, if you were to take each input through a number of separate paths to an adder through bit shifters, you could implement less restrictive attenuation, for example 1/3 is approximated by 1/4+1/16+1/64
 
On 2011-09-07, at 3:00 PM, Matthew Smith wrote:

> Hi Folks
> 
> Trying to figure the easiest, cheapest (in resources) way of mixing a group of signals in the digital domain (programmable logic, in this case.)
> 
> The actual mixing is simple enough - add and bit-shift. However, I want to adjust (attenuate) the input levels prior to mixing.
> 
> Whilst I could use multiplication, this sounds like rather profligate use of hardware multipliers - especially as I'm ony working against what's effectively a constant, rather than a changing value.
> 
> Given a 12-bit value, would it be adequate to provide attenuation with a simple bit-shift to knock off however many LSBs?
> 
> Cheers
> 
> M
> 
> -- 
> Matthew Smith
> 
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