Paul,
I would also be interested in how you built your simulator.
I'm considering building a simple one myself.
I'll probably have mine just toggle the phase every 100 ms initially.
Dale
-----Original Message-----
From: paul swed
Sent: Sunday, October 21, 2012 11:08 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] WWVB New Modulation five cent demodulator / carrier
regenerator ?
Jameco had them on sale for 20 cents each so I purchased some.
Moved the clock up frequency for 60 Khz and injected the 60Khz BPSK. (I
built a simulator) It did not track and in general produced noise. I
understand you can use 2 frequencies to drive it and I tried both from
synth gens.
I was looking at the RDS decoders and the data seemed to be differential.
Set it aside at that point. I am curious as to why it did not work. Like
everyone here would be great if it worked....
Regards
Paul
WB8TSL
On Sun, Oct 21, 2012 at 10:55 PM, Dale J. Robertson <[email protected]> wrote:
Paul,
I'm trying to understand your reference to 'differential BPSK' all the
RDS references I've looked at indicate a 180 degree phase shift just like
WWVB. I'm thinking that differential and antipodal are just different
words
for the same thing
Regards,
Dale
Sent from my iPhone
On Oct 21, 2012, at 10:03 PM, paul swed <[email protected]> wrote:
> Because it use differential BPSK. I have a number of them and was trying
> it. There is a test pin that might make it useful.
> Regards
> Paul
> WB8TSL
>
> On Sun, Oct 21, 2012 at 9:14 PM, Dale J. Robertson <[email protected]>
wrote:
>
>> While looking for other stuff I came across the data sheet for the NXP
>> Semi SAA6579.
>> The chip is a purpose built demodulator for RDS (which utilises a 57
>> KHz
>> ABPSK subcarrier on FM broadcast that is) used for traffic, song info
etc.
>> This chip has an anti-aliasing front end low pass filter and an 8th
order
>> bandpass filter followed by a costas loop and provides a phase
synchronous
>> regenerated carrier. What's interesting is that the switched cap
bandpass
>> filter and the synchronous detector are both driven by clocks derived
from
>> a local crystal oscillator which is spec'd at 4.332 or 8.664 MHz (76 or
152
>> X carrier chosen by a mode select pin) I'm thinking it should be
possible
>> to use a 4.56 or 9.12 MHz crystal or external clock to use this chip
as-is
>> on 60 KHz.
>> Have a look at the data sheet and tell me why I'm full of it.
>> Jameco is closing out these chips in DIP-16 at a nickel apiece,
>> $3.00/hundred.
>>
>> Dale NV8U
>>
>>
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