[time-nuts] KD2BD WWVB receiver/decoder in QEX

paul swed paulswedb at gmail.com
Mon Nov 23 13:28:46 EST 2015


Charles I did see the slew rates and bandwidth and came to the conclusion
those were not issues. Thats why I will build up a test board pretty
quickly to confirm the component values still work. They should. It also
means I do not need to wait for the LM873s to showup. Lots can be wired
without the LMC6484s.
Regards
Paul
WB8TSL

On Mon, Nov 23, 2015 at 12:16 PM, Charles Steinmetz <csteinmetz at yandex.com>
wrote:

> Paul wrote:
>
> post down conversion to 10 Khz I was scratching my head as to why not
>> the TL08X series.
>>
>
> Input voltage noise.  Unless you need the low input current of the FET
> part, there is no need to take the noise hit.  If you *do* need the low
> input current, there are 4 or 5 generations of FET-input opamps that are
> all far superior to the TL0xx parts.  Take a look at the OPA134/2134/4134,
> for example.  (I haven't used TL0xx opamps since the '70s.)
>
> BTW:  I suggested using NE5532s instead of LM387s and said they were
> better in every way.  Comparing the LM387 to the NE5532, one might notice
> that the bandwidth spec of the 5532 is lower (10MHz) than that of the 387
> (15MHz).  But what is important for most applications is not the
> small-signal BW, it is the power BW (full-output BW), which depends on the
> slew rate, not on the SSBW.  The 5532's 9v/uS slew rate supports a PBW of
> 140kHz, while the 387's PBW is only 75kHz (S/R is not stated).  (This tells
> us two things -- first, that the 387's slew rate must be <5v/uS; and
> second, that the 387 has less phase margin than the 5532.)
>
>
> Best regards,
>
> Charles
>
>
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