Problem with FIR II core

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Hi kaz,

It is still not clear to me. Lets me try I understand your block diagram first

I have 16 bit data stream 288MHz sample rate [... s7 s6 s5 s4 s3 s2 s1 s0 ... ] lets assume s0 is old sample, s7 is more recent sample

I get my stream in 64 bit packets like this

...

[s3 s2 s1 s0]

[s7 s6 s5 s4]

...

those quads I get on each 72 Mhz tick

1. From DSP perspective what I want to achieve is to filter my 288Mhz data stream with simple single channel FIR filter

https://alteraforum.com/forum/attachment.php?attachmentid=15769&stc=1

(Please see 1.png)

to do this I need to serialize my quads

In your "option 1" you suggest clk = 4 x72=288MHz ,so I think you suggest this structure?

But why you suggest 4 channels then? I need a single 288MHz filter and not 4 independent filters.

(In your suggesting I don't know what "sample rate = 72" would mean.

I tested that this setup brings 16 bit avalon bus width.)

2. Your second suggestion seems to be something like this + output multiplexer:

(Please see 2.png)

Have I understood correctly?

Do you suggest that i have to calculate the impulse response of the above 4 filters such that if i multiplex their outputs with 288mhz rate i get the result I am after?

(Edit: In fact it should be not a MUX but a Summation block and the FIR clocks should be 25% shifted ... for now I am just trying to get the global picture )

On a DSP controller the block processing (processing the data stream chunk by chunk) is something very standard.

I am surprised that this appear as something not standard in the FPGA world, or am I misunderstood?

Thank you

Dimitar

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I see your new description different . So you have one stream data (16 bits wide) @ 288Msps...yes?

Then the next line of:

[s3 s2 s1 s0]

[s7 s6 s5 s4]

means your stream is in two parallel paths. If so you need to run clock at 288*2

If that is too fast then you are aiming at two paths filtering. This is hard and you will need a lot work to get it right (Google: even/odd filter streaming).

Have I understood you?