I am curious if the first local oscillator on a GPS receiver must actually
be locked or coherent to the reference oscillator in the GPS receiver
typically running at some 10 MHz approximately. Or as long as the first LO
is quite stable it doesn't matter because the receiver can track the code.
This
> I am curious if the first local oscillator on a GPS receiver must actually
> be locked or coherent to the reference oscillator in the GPS receiver
> typically running at some 10 MHz approximately. Or as long as the first LO
> is quite stable it doesn't matter because the receiver can track the co
Hi
There is a limited tracking range for Doppler. You would need to stay inside
that.
Bob
Sent from my iPhone
> On Mar 30, 2017, at 9:46 AM, paul swed wrote:
>
> I am curious if the first local oscillator on a GPS receiver must actually
> be locked or coherent to the reference oscillator in
On 3/30/17 10:32 AM, Bob Camp wrote:
Hi
There is a limited tracking range for Doppler. You would need to stay inside
that.
Doppler is pretty big when the spacecraft is coming or going at the
horizon, about 5 kHz (out of 1.5 GHz, so 4-5 ppm).
Relatively speaking, GPS satellites are moving s
On 3/30/17 11:06 AM, Peter Monta wrote:
I am curious if the first local oscillator on a GPS receiver must actually
be locked or coherent to the reference oscillator in the GPS receiver
typically running at some 10 MHz approximately. Or as long as the first LO
is quite stable it doesn't matter bec
Hi
> On Mar 30, 2017, at 7:05 PM, jimlux wrote:
>
> On 3/30/17 10:32 AM, Bob Camp wrote:
>> Hi
>>
>> There is a limited tracking range for Doppler. You would need to stay inside
>> that.
>>
>
> Doppler is pretty big when the spacecraft is coming or going at the horizon,
> about 5 kHz (out
Thanks everyone for your comments. It will be a GPSDP TBolt or Z3801
reference.
I just wanted to eliminate some variables at this stage.
Regards
Paul
WB8TSL
On Thu, Mar 30, 2017 at 7:56 PM, Bob kb8tq wrote:
> Hi
>
>
> > On Mar 30, 2017, at 7:05 PM, jimlux wrote:
> >
> > On 3/30/17 10:32 AM, Bob
>
> BTW a lot of GPS receivers don't have a "first LO".. they are more like a
>> Tuned RF receiver - an input BPF for L1, L2, or L5, then direct sampling at
>> around 30-40 MHz - something that makes the GPS signals alias down
>> somewhere convenient (and always have positive frequency offset from
On Thu, 30 Mar 2017 20:00:31 -0700
Peter Monta wrote:
> > BTW a lot of GPS receivers don't have a "first LO".. they are more like a
> >> Tuned RF receiver - an input BPF for L1, L2, or L5, then direct sampling at
> >> around 30-40 MHz - something that makes the GPS signals alias down
> >> somewh
On Thu, 30 Mar 2017 19:56:31 -0400
Bob kb8tq wrote:
> > Doppler is pretty big when the spacecraft is coming or going at the
> > horizon, about 5 kHz (out of 1.5 GHz, so 4-5 ppm).
> > Relatively speaking, GPS satellites are moving slowly (a few km/s)
> >
>
> So somewhere in the baseband process
On 3/31/17 4:35 AM, Attila Kinali wrote:
On Thu, 30 Mar 2017 20:00:31 -0700
Peter Monta wrote:
BTW a lot of GPS receivers don't have a "first LO".. they are more like a
Tuned RF receiver - an input BPF for L1, L2, or L5, then direct sampling at
around 30-40 MHz - something that makes the GPS
links [2] and [3] give 404 errors
Dave
-Original Message-
From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Attila Kinali
Sent: 31 March 2017 12:35
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] GPS first LO need to be locked?
[2] &q
Hi,
On 03/30/2017 03:46 PM, paul swed wrote:
I am curious if the first local oscillator on a GPS receiver must actually
be locked or coherent to the reference oscillator in the GPS receiver
typically running at some 10 MHz approximately. Or as long as the first LO
is quite stable it doesn't matt
Hi Jim,
On 03/31/2017 01:07 AM, jimlux wrote:
BTW a lot of GPS receivers don't have a "first LO".. they are more like
a Tuned RF receiver - an input BPF for L1, L2, or L5, then direct
sampling at around 30-40 MHz - something that makes the GPS signals
alias down somewhere convenient (and always
God kväll Magnus,
On Fri, 31 Mar 2017 21:19:00 +0200
Magnus Danielson wrote:
> Still fills the function of LO, as the sample and hold operates as a
> mixer and the fold-down can be seen as an overtone mix followed by a
> sampling of the mix product, so well, it's about the same thing.
"Harmon
God natt Attila,
On 03/31/2017 11:29 PM, Attila Kinali wrote:
God kväll Magnus,
On Fri, 31 Mar 2017 21:19:00 +0200
Magnus Danielson wrote:
Still fills the function of LO, as the sample and hold operates as a
mixer and the fold-down can be seen as an overtone mix followed by a
sampling of the
Hi
There are a lot of GPS chips that do an I/Q mix down to a low IF. It’s then
(re) sampled from there. The “LO” in this case would down convert to the low IF
….
Bob
> On Mar 31, 2017, at 6:08 PM, Magnus Danielson
> wrote:
>
> God natt Attila,
>
> On 03/31/2017 11:29 PM, Attila Kinali wro
Thanks everyone but I am working on an austron 2201a so all the discussions
on modern methods won't help. Whats is interesting is indeed the 2201 down
converts to 80KHz and the does sample in an IQ fashion. Its all discreet
chips and such.
Easily traceable and logical.
I think I have what I asked f
Hi
> On Apr 1, 2017, at 11:18 AM, paul swed wrote:
>
> Thanks everyone but I am working on an austron 2201a so all the discussions
> on modern methods won't help. Whats is interesting is indeed the 2201 down
> converts to 80KHz and the does sample in an IQ fashion. Its all discreet
> chips and
nali
> Sent: 31 March 2017 12:35
> To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] GPS first LO need to be locked?
>
> [2] "A Prototyping Platform for Multi-Frequency GNSS Receivers", by Akos,
> Ene and Thor, 2003 http://waas.stanfo
-Original Message-
From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Attila
Kinali
Sent: 31 March 2017 12:35
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] GPS first LO need to be locked?
[2] "A Prototyping Platform for Multi-Frequenc
[3] give 404 errors
>>>
>>> Dave
>>>
>>> -----Original Message-----
>>> From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Attila
>>> Kinali
>>> Sent: 31 March 2017 12:35
>>> To: Discussion
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