No need to be confused , lets put it together again:
The USB benchmark software can be found in the
What do you mean by another disk? are both gnuradrio installation
work from the same operating system ? or each drive has its own OS?
What is you OS?
What is the reading of [hdparm -t /mnt/sda ] on both drives?
Describe you setup please and what do you want to do. Fortunately,
for one day or less, I have function generator and spectrum analyzer in
my home with the USRP system and I can run a copy of your experiments at
my home to see the result on my system.
Vincenzo P. [email protected] wrote: I’m recording and
replaying interleaved shorts @ 8Msps… how is the benchmarking software
called? I also have noticed a diffference between my main, old gnuradio
installation and a fresh one just done from trunk on another disk… the
fisrt is all right with transmissions up to 4 MHz the second stops at
2MHz, (using the same scripts of mine on both installations): when, on
the fresh installation, I ask for 4MHz I can hear only noise being sent
out (I think this is a different problem than the slow flow)… I’m a bit
2007/9/7, Firas abbas [email protected]: Hi Vincenzo,
Are you recording the 8Msps complex or short ?. In recording, I always
prefer the interleaved complex short, because the real coming samples
from the USRP across the USB is 16 bit short. The conversion to float
(32 bit) complex is being done by software in the PC and thus adds no
new information and does not enhance the data. It only complicate file
storage process. If converting to short does not solve your problem, try
to record and play smaller bandwidth like 6.4MHz (decimation 10) or
less. Also test your PC USB 2 speed by using the benchmark software
found the gnuradio truck.
Vincenzo P. < [email protected]> wrote:
hi Firas, thanks for help!
i’m doing pretty much everything you suggested, and in fact, really!!, I
do think that my HD is doing a very good work.
nevertheless I keep having the same problem,
this is what I also posted to the list:
I finally have a 7200rpm disk that does keep up very well with 32MBps
and, I guess, even much more…
is then this assumption correct?
8Msps with gr_complex data type ==> 8e6*8bytes per sample = 64 MB/s
8Msps with interleaved shorts ==> 8e6*2bytes per int * 2channels = 32
I’m sure now that my drive can keep up with recording and replaying the
and I guess that even 64 with my new, xfs formatted clean disk is fine
my problem is that in both cases ( both using complex and interleaved
If I work with a 4 MHz bandwidth everything looks allright.
I can record and replay a 4 MHz fm band and perfectly listen to the
station at the center of it when sending it back to the receiver
when I try to go 8 MHz I can hear a noisy, extremely weak replica of my
signal, which is SLOW… like an old cassette player with flat batteries
and this is consistent with the fact that a file meant to last 10.717
secs @ 32MB/s, when played with usrp_interp= 16 (8MHz Bandwidth)
lasts MORE than 13 secs, while if played with usrp_interp=32 (4MHz),
it lasts exactly the double of the correct value ie: 10.717*2=21.434
has this ever happened to anybody… am I making huge mistakes that I
havent discovered yet?
On Wed, 2007-09-05 at 13:15 -0700, Firas abbas wrote:
Sorry for this delay, but I didn’t saw your email in the mailing list
which I usually check. To solve your problem do :
- Buy SATA II harddisk drive
- Put Linux in ext3 partition
- Create a small Ext2 partition for your recordings (about
Vincenzo P. wrote:
On Mon, 2007-09-03 at 20:04 -0700, Eng. Firas wrote:
> Hi Vincenzo,
storing a very few secs of my sample stream to the ram before
> Vincenzo P. wrote:
> > the second was 2MHz
> > could hear that the samples were not being sent out at
8Msps: the very
> > poor audio was also “slow” as it happens when you set the
> > rate too high, compared to the sample rate your samples
were taken at…
> > well, this is not just some attenuation next to the
shoulder of my ofdm
> > signal… this is the whole signal … gone…