Re: Volk machine

Nick:

I tried downsampling the 25MHz to 10, but still was not recording the
whole
time I ran (about 10 seconds, with only a couple seconds of playback).
That
was when I tried using a RAM disk, albeit at 50 downsampled to 30. I am
using the following for my disk:

mount -o size=1G -t tmpfs none /mnt/tmpfs

I then store my data file to /mnt/tmpfs

Am I doing that wrong? Or is there some other explanation for not
storing
data (other than storage size)?

Again, all feedback and help is appreciated.

Nick F. [email protected] wrote:

Paul,

30MHz is a big chunk of data to be streaming to anything. A 4GB ramdisk
will be full in 30 seconds at this rate. Do you really not know a
priori
where
in the whole 0-30MHz spectrum your signal will be?

I notice now in your first post that you’re streaming 25Msps with a
low-pass filter to 10MHz – if this is the case, why use a 25Msps rate
in
the first place? You can make the USRP work for you by asking for 10Msps
(or less, if you know you need less bandwidth) – it’ll handle the
downsampling and filtering.

–n

What was the size of the recorded file on the RAM disk? Are you seeing
“O”
indications (for overflow)?

–n