[hpsdr] Polyphase filters

[Phil Harman]

Hi Steve,

I also did a little Googling for Polyphase filters this week and found
enough information to be dangerous.

I was able to simulate a FIR decimating Polyphase filter using an Excel
spreadsheet and it seems to work just fine.

One thing that I have not been able to resolve is what you do if your
decimation value is greater than the number of taps in your FIR. Perhaps
one of our members can enlighten me,

BTW, the current maximum baseband bandwidth of 192kHz is not a restriction
of the hardware - a few changes to the Verilog code in Mercury would
enable a higher sampling rate.

For those interested in doing some Verilog development there is the
possibility of using a high speed LVDS connection between Mercury and Ozy
in order to run at a  sampling rate only limited by the performance of the
USB2 interface.

Using an LVDS interface would also free up logic gates currently used by
nWire with the potential of implementing more receivers.

.... and absolutely....too many projects!

73's Phil...VK6APH

> ***** High Performance Software Defined Radio Discussion List *****
>
> If we got it implemented in verilog on Mercury we would not be limited to
> the 192K base band per receiver but could have different receivers each
> with
> different base bands. So we could then have for example a receiver for
> each
> of the amateur bands. Googling around I have discovered some verilog
> implementations and even some IP cores are already available.
>
> Ah too many interesting projects around !
>
> 73s
>
> Steve
> G1YLB
>
> --------------------------------------------------
> From: "Frank Brickle" <brickle at pobox.com>
> Sent: Tuesday, July 06, 2010 6:52 PM
> To: "Steve Doyle" <steve_doyle at o2.co.uk>
> Subject: Re: [hpsdr] Polyphase filters
>
>> Polyphase filterbanks of this kind are at the heart of the new version
>> of DttSP currently in development.
>>
>> 73
>> Frank
>> AB2KT
>>
>> On Tue, Jul 6, 2010 at 9:18 AM, Steve Doyle <steve_doyle at o2.co.uk>
>> wrote:
>>> ***** High Performance Software Defined Radio Discussion List *****
>>>
>>> Hi,
>>>
>>> This weeks teamspeak peaked my interest when when someone mentioned the
>>> potential of polyphase filters as the solution to multiple receivers, I
>>> think someone mentioned 100 separate receivers !
>>>
>>> Anyway I came across the following tutorial, the math is beyond me but
>>> the matlab program doesn't look to bad.
>>>
>>> Www.signumconcepts.com/download/paper035.pdf
>>>
>>> Interesting stuff
>>>
>>> 73s
>>>
>>> Steve
>>> G1ylb
>>>
>>>
>>> Sent from my iPhone
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>>
>>
>>
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