[hpsdr] Mercury

[John B. Stephensen]

The 52 4.5k RAM blocks are the equivalent of 13 18k RAM blocks so it might
barely work for the OFDM modem application if processing speed can be
maintained and the RAM usage can be shrunk by using smaller memories for a
256-point maximum size FFT. HSMM members would be disappointed as they want
to fill a 6 MHz channel with 6 kHz spaced subcarriers. This subcarrier
spacing allows a 41 microsecond guard interval to reject multipath.

Xilinx seems to consistantly implement a higher memory to logic ratio than
Altera. The EP2C20 does have twice the number of logic elements, but the
XC3S500E offers 23% more memory for less money ($26 vs. $42).

73,

John
KD6OZH

----- Original Message ----- 
From: "Eric Blossom" <eb at comsec.com>
To: "Lyle Johnson" <kk7p at wavecable.com>
Cc: "John B. Stephensen" <kd6ozh at comcast.net>; <hpsdr at hpsdr.org>
Sent: Sunday, June 11, 2006 03:49 UTC
Subject: Re: [hpsdr] Mercury


> On Sat, Jun 10, 2006 at 08:24:38PM -0700, Lyle Johnson wrote:
> > ***** High Performance Software Defined Radio Discussion List *****
> >
> > > It would be nice to have at least as many resources as a Xilinx
XC3S400 (16
> > > 18k dual-port RAMs, 16 18x18 multipliers and 7200 logic elements).
> >
> > The Altera EP2C8 is the largest Cyclone II device I can find in a
> > non-BGA package.  It has 165,888 bits of SRAM (36 blocks of 4K bits), 18
> > 18x18 multipliers and 8256 logic elements.  $24 in singles from the
> > Altera online store.
> > 73,
> >
> > Lyle KK7P
>
> They've announced an EP2C20 in a QFP-240 package, though it's not yet
> available.  Might be worth a call to Altera to find out when it'll
> really be ready.
>
> Eric


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