[time-nuts] WWVB cheap chip saa6579 RDS decoder back to the chip

[paul swed]

Henry
Its been a while since that thread and I have not done anything with the
chip. But to answer your questions.
Really good signal to noise. The modulator is 6" from the saa6579. Its a
home brew BPSK modulator and the transitions are programmable. But I am
following wwvbs 1sec per bit. So the phase is quite stable for long periods
of time. Signal level is 1000uv but again that can be adjusted.
Were is someone. My comment was someone on time-nuts suggested that you had
to use the clock and a flip flop to properly see the data. Thats what you
are also saying.
As to the wwvb modulation scheme I fully understand that. But I actually do
not know a lot about RDS and how it might be different from wwvbs method of
transmission.
I believe there is plenty of information on RDS. I just don't have a lot of
time to figure it out.
I will get back to the chip at some point it is really interesting but very
poorly documented unfortunately.
Regards
Paul
WB8TSL

On Thu, Nov 15, 2012 at 7:14 PM, ehydra <ehydra at arcor.de> wrote:

> paul swed schrieb:
>
>  To the saa6579
>> As mentioned in the other thread.
>> Simple to hook up.
>> Cheap
>> Requires 1000uv or more so that ends up making things more complicated.
>>
>
> S/N is important, not so absolute amplitude.
>
>
>
>  But in my case simply did not really work at 57 or 60 Khz.
>>
>
> The chip looks for correct phase for about 50ms (max. 100ms). Did you
> check carefully that in this time-frame the phase never inversed or
> amplitude dropped down temporary?
>
> Maybe you misunderstood the modulation scheme anyway? It is not native
> BPSK!
>
>
>
>  As some someone pointed out you may have to take the clock and data to a
>> flip flop to get the correct information.
>>
>
> Where is "someone"?
>
> As I understood the datasheet you get maximum processing time (set-up
> time) for the data-bit if you use a D-FF delaying DATA strobed by CLOCK.
>
> - Henry
>
> --
> ehydra.dyndns.info
>
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