I'll look for them!
Don
Bruce Griffiths
> Don
>
> One potential problem with most USB sound cards is the preamp.
> The gain of these is set by a front panel pot over a very wide range.
> Consequently the preamp gain cannot be all that stable.
> Unless these preamps can be bypassed they may limit t
tin
PDS
From: Hal Murray
Subject: Re: [time-nuts] Using cheap sound cards for measurements
james.p@jpl.nasa.gov said:
[External clock at strange frequency.]
> That's an interesting idea. I would imagine that the clock going into
> the chip is probably some multiple of the sample
Don
One potential problem with most USB sound cards is the preamp.
The gain of these is set by a front panel pot over a very wide range.
Consequently the preamp gain cannot be all that stable.
Unless these preamps can be bypassed they may limit the performance when
used for measurements.
Bruce
D
Well, I've just ordered two $9.98 USB sound "cards" on good ol' ebay. It
will take some time to get here from China. I'll however have no
compunction about opening up and so forth. Maybe some secrets will spill
out :-). Still will not beat the EMU 0202 probably but when wrecked by
fiddling will not
Hal Murray wrote:
james.p@jpl.nasa.gov said:
[External clock at strange frequency.]
That's an interesting idea. I would imagine that the clock going into
the chip is probably some multiple of the sample rate (e.g. 48kHz*16*2
= 1.536 MHz), so you could pick the closest 1/N from 10 MHz and p
james.p@jpl.nasa.gov said:
[External clock at strange frequency.]
> That's an interesting idea. I would imagine that the clock going into
> the chip is probably some multiple of the sample rate (e.g. 48kHz*16*2
> = 1.536 MHz), so you could pick the closest 1/N from 10 MHz and pump
> that in.
Thanks, Demian. At least one of the SD radio programs uses an ASIO driver.
I do not know about the rest, or about the "leading" spectrum analysis
freebies that are out there.
Don
Demian Martin
> Be careful of the Emu/Creative stuff. They have always has resampling in
> their products in the past.
Be careful of the Emu/Creative stuff. They have always has resampling in
their products in the past. This new generation doesn't but it still has an
inline DSP to muck around with the bits. Also the Windows (and MAC) sound
systems are notorious for resampling internally. This can be very hard to
ge
My limited experience with this USB soundcard was the ease of getting it
working with Windows Vista home premium.
Another PCI sound card, the Delta 44, was a big problem, at least for me.
Stan, W1LE
Don Latham wrote:
Ok, I have looked at a few USB cards and reviews. For SD radios, and
as fa
Ok, I have looked at a few USB cards and reviews. For SD radios, and as far
as I can tell for time use, the Creative E-MU 0202 will do nicely, at a
reasonable cost of $99.00.
According to the company info, the E-MU 0404 might be synchronizable; it
costs about $150. The plug-in card (takes two sl
On 8/22/09 5:37 AM, "Hal Murray" wrote:
>
>
>>> Add internal or external (5/10 MHz) clock.
>
>> None will have that... Maybe a multiple of 48 or 44.1 kHz
>
> The key idea is to have an external clock input. I don't think the frequency
> is critical for our usage.
>
> All the audio chips
>> Add internal or external (5/10 MHz) clock.
> None will have that... Maybe a multiple of 48 or 44.1 kHz
The key idea is to have an external clock input. I don't think the frequency
is critical for our usage.
All the audio chips I've looked at have a DSP filter that scales with the
clock f
Lux, Jim (337C) wrote:
On 8/21/09 8:09 PM, "Tom Van Baak" wrote:
Add internal or external (5/10 MHz) clock.
/tvb
None will have that...
Maybe a multiple of 48 or 44.1 kHz
Wordclock is common. Black burst is rare. 5 or 10 MHz is yeat a level of
conversions away. It will not be a cheap
ment"
Sent: Saturday, August 22, 2009 3:42 PM
Subject: Re: [time-nuts] Using cheap sound cards for measurements
I'm looking to stay under $200, but that's why I want USB if that makes
any sense...
Don
Hal Murray
On this track, what's the group opinion as to the best U
M
Subject: Re: [time-nuts] Using cheap sound cards for measurements
I'm looking to stay under $200, but that's why I want USB if that
makes
any sense...
Don
Hal Murray
On this track, what's the group opinion as to the best USB sound
"card"? I'm looking for one
On 8/21/09 8:09 PM, "Tom Van Baak" wrote:
> Add internal or external (5/10 MHz) clock.
>
> /tvb
None will have that...
Maybe a multiple of 48 or 44.1 kHz
>
>> Add balanced inputs to the list of desirable features.
>>
>> Bruce
>> Don Latham wrote:
>>> On this track, what's the group opin
that have
high sample rates etc, but they use special drivers to work. Emu has several
high performance boxes to consider. Linux support is problematic. . .
Demian Martin
PDS
From: "Don Latham"
Subject: Re: [time-nuts] Using cheap sound cards for measurements
To: "Discussion of p
I'm looking to stay under $200, but that's why I want USB if that makes
any sense...
Don
Hal Murray
>
>> On this track, what's the group opinion as to the best USB sound
>> "card"? I'm looking for one for time as well as sd radio use. Should
>> have the best separation, best s/n, highest digitizat
OK, why not?
Don
Tom Van Baak
> Add internal or external (5/10 MHz) clock.
>
> /tvb
>
>> Add balanced inputs to the list of desirable features.
>>
>> Bruce
>> Don Latham wrote:
>>> On this track, what's the group opinion as to the best USB sound
>>> "card"?
>>> I'm looking for one for time as well
> On this track, what's the group opinion as to the best USB sound
> "card"? I'm looking for one for time as well as sd radio use. Should
> have the best separation, best s/n, highest digitization rate, 24 bit,
> etc. Any recommendations?
I'd be interested in not-quite-best or even far-from-best
Add internal or external (5/10 MHz) clock.
/tvb
Add balanced inputs to the list of desirable features.
Bruce
Don Latham wrote:
On this track, what's the group opinion as to the best USB sound "card"?
I'm looking for one for time as well as sd radio use. Should have the best
separation, best s
Add balanced inputs to the list of desirable features.
Bruce
Don Latham wrote:
> On this track, what's the group opinion as to the best USB sound "card"?
> I'm looking for one for time as well as sd radio use. Should have the best
> separation, best s/n, highest digitization rate, 24 bit, etc. Any
On this track, what's the group opinion as to the best USB sound "card"?
I'm looking for one for time as well as sd radio use. Should have the best
separation, best s/n, highest digitization rate, 24 bit, etc. Any
recommendations?
Thanks
Don
Bruce Griffiths
> Tom Van Baak wrote:
>> Could you sync
Tom Van Baak wrote:
> Could you sync the sounds cards in software?
>
> If you feed an external 1 PPS into the unused stereo channel of
> each sound card, then you can solve both card-to-card phase
> differences as well as card-to-card frequency differences with
> simple software fitting after, or e
Could you sync the sounds cards in software?
If you feed an external 1 PPS into the unused stereo channel of
each sound card, then you can solve both card-to-card phase
differences as well as card-to-card frequency differences with
simple software fitting after, or even while, samples are being
c
Lux, Jim (337C) wrote:
>
>> -Original Message-
>> From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
>> Behalf Of Bruce Griffiths
>>
>> If the 2 signals are sampled at different times then there is
>> incomplete
>> cancellation of the phase noise of the offset oscill
> -Original Message-
> From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
> Behalf Of Bruce Griffiths
>
> If the 2 signals are sampled at different times then there is
> incomplete
> cancellation of the phase noise of the offset oscillator.
> This effect increases wi
Lux, Jim (337C) wrote:
>> -Original Message-
>> From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
>> Behalf Of Mark Sims
>> Sent: Friday, August 21, 2009 3:06 PM
>> To: time-nuts@febo.com
>> Subject: [time-nuts] Using cheap sound
Product Design Services
Date: Fri, 21 Aug 2009 22:06:28 +
From: Mark Sims
Subject: [time-nuts] Using cheap sound cards for measurements
To:
Message-ID:
Content-Type: text/plain; charset="iso-8859-1"
Just because the cards have the same ADC clock does not mean that they will
be s
ug 2009 22:51:40 +0200
From: Christian Vogel
Subject: Re: [time-nuts] Using cheap sound cards for measurements
To: Discussion of precise time and frequency measurement
Message-ID: <4a8f08dc.6010...@vogel.cx>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Hi Lux,
>
> -Original Message-
> From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
> Behalf Of Mark Sims
> Sent: Friday, August 21, 2009 3:06 PM
> To: time-nuts@febo.com
> Subject: [time-nuts] Using cheap sound cards for measurements
>
>
> Just
Just because the cards have the same ADC clock does not mean that they will be
sampling at the same time. There will be differences in the startup
characteristics, register programming, etc. that can affect just when the
input is sampled. They may be sampling at the same rate, but the card
Lux, Jim (337C) wrote:
The idea of using a standard stereo sound card interface to do Allan deviation
measurements has been discussed on the list in the past (i.e. Beat the two
signals down to some convenient audio frequency, digitize, and find zero
crossings by curve fits to the sampled data)
Locating the zero crossing of the signal isnt the best approach.
If one uses some DSP the phase shifts between the 2 beat notes can be
measured without the sound card sampling frequency stability making a
significant contribution to the noise.
Lux, Jim (337C) wrote:
>>> Wouldn't the cards need to
time and frequency measurement
>> Subject: Re: [time-nuts] Using cheap sound cards for measurements
>>
>>
>> That particular method is vulnerable to RF pickup from within the PC.
>> The coax screen should be RF grounded at both ends.
>>
>> Bruce
>>
> > Wouldn't the cards need to be synchronized, though? Essentially,
> > you're still comparing the two signals with each other, just
> > doing it in software, rather than in hardware, in the classical
> > time interval counter scheme counting 1Hz (or 123Hz). Syncing
> > inexpensive cards is a r
e and frequency measurement
> Subject: Re: [time-nuts] Using cheap sound cards for measurements
>
>
> That particular method is vulnerable to RF pickup from within the PC.
> The coax screen should be RF grounded at both ends.
>
> Bruce
>
> Christian Vogel wrote:
> >
That particular method is vulnerable to RF pickup from within the PC.
The coax screen should be RF grounded at both ends.
Bruce
Christian Vogel wrote:
> Hi Lux,
>> Syncing inexpensive cards is a real chore (and the only reason to be
>> thinking about using this in the first place is to keep the c
> > If isolation turns out to be a problem, I imagine it would be
> practical to
> > use two separate sound cards. It may not be practical to
> compensate for the
> > frequency-dependent effects of channel leakage, but timing/rate
> differences
> > between two independent cards should be less im
Hi Lux,
Syncing inexpensive cards is a real chore (and the only reason to be
thinking about using this in the first place is to keep the cost to a
minimum, otherwise, you might as well build a special purpose little
box with counters & A/Ds, and an interface)
I've had too many problems with che
> -Original Message-
> From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
> Behalf Of John Miles
> Sent: Friday, August 21, 2009 11:59 AM
> To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] Using cheap sound card
..@febo.com [mailto:time-nuts-boun...@febo.com]on
> Behalf Of Lux, Jim (337C)
> Sent: Friday, August 21, 2009 6:45 AM
> To: Discussion of precise time and frequency measurement
> Subject: [time-nuts] Using cheap sound cards for measurements
>
>
> The idea of using a standard s
The idea of using a standard stereo sound card interface to do Allan deviation
measurements has been discussed on the list in the past (i.e. Beat the two
signals down to some convenient audio frequency, digitize, and find zero
crossings by curve fits to the sampled data).
Several have commented
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