Jim, you're right a DAC is not needed: I was thinking of generating the
BPSK by a DAC but it is not necessary. I have seen some BPSK hardware
modulators: easier than generating samples and feeding a DAC.
On Fri, Dec 16, 2011 at 7:42 PM, Hal Murray hmur...@megapathdsl.net wrote:
On 12/17/2011 02:37 PM, Azelio Boriani wrote:
Jim, you're right a DAC is not needed: I was thinking of generating the
BPSK by a DAC but it is not necessary. I have seen some BPSK hardware
modulators: easier than generating samples and feeding a DAC.
For a single bird a digital output could be
Correct: I was thinking how to simulate an only bird. The RACAL GPS101 is a
single channel simulator and maybe made that way. Then it is possible to
place a number of 1 channel simulators at a distance...
On Sat, Dec 17, 2011 at 3:18 PM, Magnus Danielson
mag...@rubidium.dyndns.org wrote:
On
On 12/17/11 6:58 AM, Azelio Boriani wrote:
Correct: I was thinking how to simulate an only bird. The RACAL GPS101 is a
single channel simulator and maybe made that way. Then it is possible to
place a number of 1 channel simulators at a distance...
I was thinking more along the lines of how
On 12/17/2011 05:10 PM, Jim Lux wrote:
On 12/17/11 6:58 AM, Azelio Boriani wrote:
Correct: I was thinking how to simulate an only bird. The RACAL GPS101
is a
single channel simulator and maybe made that way. Then it is possible to
place a number of 1 channel simulators at a distance...
I
On 12/17/11 9:01 AM, Magnus Danielson wrote:
On 12/17/2011 05:10 PM, Jim Lux wrote:
On 12/17/11 6:58 AM, Azelio Boriani wrote:
Correct: I was thinking how to simulate an only bird. The RACAL GPS101
is a
single channel simulator and maybe made that way. Then it is possible to
place a number of
On 12/17/2011 11:10 AM, Jim Lux wrote:
On 12/17/11 6:58 AM, Azelio Boriani wrote:
Correct: I was thinking how to simulate an only bird. The RACAL
GPS101 is a
single channel simulator and maybe made that way. Then it is possible to
place a number of 1 channel simulators at a distance...
I
On 12/17/2011 09:57 PM, Jim Lux wrote:
L1 C/A
But the real question isn't how to generate the signals (that's straight
forward).. it's how good does the oscillator have to be to effectively
test the receiver, in the sense of measuring it's timing performance.
A decent OCXO should be able to
On 12/17/11 2:56 PM, Magnus Danielson wrote:
On 12/17/2011 09:57 PM, Jim Lux wrote:
L1 C/A
But the real question isn't how to generate the signals (that's straight
forward).. it's how good does the oscillator have to be to effectively
test the receiver, in the sense of measuring it's timing
Hi Jim,
On 12/18/2011 01:25 AM, Jim Lux wrote:
On 12/17/11 2:56 PM, Magnus Danielson wrote:
On 12/17/2011 09:57 PM, Jim Lux wrote:
L1 C/A
But the real question isn't how to generate the signals (that's straight
forward).. it's how good does the oscillator have to be to effectively
test the
Hi Magnus:
Exactly. The main problem with the Transit system was that the receiver needed a Cs clock for the system to work at
all. GPS removed that requirement.
It's my understanding that a GPS receiver that uses a Cs clock has much more
capability.
Have Fun,
Brooke Clarke
Hi Brooke,
On 12/18/2011 03:30 AM, Brooke Clarke wrote:
Hi Magnus:
Exactly. The main problem with the Transit system was that the receiver
needed a Cs clock for the system to work at all. GPS removed that
requirement.
Indeed. Most of that was due to the long observations times as I recall
jim...@earthlink.net said:
But the real question isn't how to generate the signals (that's straight
forward).. it's how good does the oscillator have to be to effectively
test the receiver, in the sense of measuring it's timing performance.
My 2 cents, which could be way off...
One of the
Maybe they used a Cs standard for the original experimental units, but
the first commercial Transit unit I saw (Magnavox MX700?) just had a
big OCXO in it - it was also all controlled by a HP2100 computer and
output the fix data onto a teletype.
The MX1102/1107 (which were pretty much standard
On 12/15/11 10:25 PM, Chris Albertson wrote:
For testing, I'd assume the gps simulator only needs to be good enough
that the receiver will detect the signal. There is some Doppler
shift so the receiver must have to look over a wider range of
frequencies so if the simulator was inside that
A used Spirent is only 26K to 37K. Interesting: playing back bits from
RAM... can it be that simple? Obvious: a DAC is required.
On Fri, Dec 16, 2011 at 3:47 PM, Jim Lux jim...@earthlink.net wrote:
On 12/15/11 10:25 PM, Chris Albertson wrote:
For testing, I'd assume the gps simulator only
On 12/16/11 7:46 AM, Azelio Boriani wrote:
A used Spirent is only 26K to 37K. Interesting: playing back bits from
RAM... can it be that simple? Obvious: a DAC is required.
No.. you don't even need a DAC. The underlying waveform is a binary
code that is BPSK modulated.
there are a variety
Slightly peripheral: Just got a bit of TI advertising with a couple of
chips of TN interest:
http://www.ti.com/product/lmk03806
http://www.ti.com/product/lmk00301
These llok very interesting. 3.3 v i think in cmos mode is enough for
most of the instrument external ref inputs.
Don
Jim Lux
On
http://www.ti.com/product/lmk03806
If anybody is collecting a list of common frequencies, there is a table in
the data sheet for that chip.
--
These are my opinions, not necessarily my employer's. I hate spam.
___
time-nuts mailing list --
Say you want a quik n easy n cheap GPS simulator to test a GPS timing
receiver. How good does the oscillator (presumably some nice multiple
of the chip rate) have to be?
My gut feel is that it needs to be, say, 10x better than the oscillator
in the receiver, and you'd compare the timing
For testing, I'd assume the gps simulator only needs to be good enough
that the receiver will detect the signal. There is some Doppler
shift so the receiver must have to look over a wider range of
frequencies so if the simulator was inside that range it could work.
Light travels at about one
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