>> On 05 Aug 2016, at 5:40 , robert bristow-johnson
<r...@audioimagination.com> wrote:
>>
>> []
>>
>> 5. how is this question different from the FIR brickwall LPF design
question for polyphase interpolation?
>
> For BLIT, these sub-sample delayed grains are usually integrated to
get a saw/square/pwm signal.
i thought that you integrated the pulse train in real time. but i
dunno. that's how i imagined BLIT was done.
When you integrate your BLIT you supress the absolute level of the
aliasing by -6dB/octave with the rest of the signal.
Though Ross was talking about BLEP where you integrate offline, then you
have the aditional roll-off before sampling.
So it's less aliasing either way?
Anyway, @ Ross, regarding the question whether 150 sample grains is long
or short,
it's short if it's oversampled and long if it's not oversampled.
For comparison: we had to use only 4 samples for oscillator-synch
transitions in a project...
If you want alias-free you should also (and maybe foremost?) look into
"sinc M" in the paper you linked (Section 3.7). Basically a slightly
squeezed truncated sinc that fits in your period seamlessly. This makes
your design questions obsolete but has it's drawbacks with synch etc.
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