Sujet : Re: Distorted Sine Wave
De : jeroen (at) *nospam* nospam.please (Jeroen Belleman)
Groupes : sci.electronics.designDate : 29. May 2024, 23:10:56
Autres entêtes
Organisation : A noiseless patient Spider
Message-ID : <v385h4$19vg4$1@dont-email.me>
References : 1 2 3 4
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On 5/29/24 22:49, Cursitor Doom wrote:
On Wed, 29 May 2024 13:42:13 -0700, john larkin wrote:
On Wed, 29 May 2024 21:43:54 +0200, Arie de Muijnck <noreply@ademu.com>
wrote:
>
On 2024-05-29 19:07, Cursitor Doom wrote:
Gentlemen,
>
Whilst fault-finding on my HP 8566B spectrum analyzer, I've found the
10Mhz reference oscillator is generating an 'unsatisfactory waveform'
which may be causing the device to be unable to lock it's main PLL.
I've come across this waveshape before, but mostly with oscillators I
was building and in the process of trying to iron out the wrinkles of
and certainly NOT a critical reference oscillator from a respected
manufacturer. Can anyone tell what's most likely going on here?
>
https://disk.yandex.com/i/z6fYbeVfPRK7aA
>
>
Looks like reflections in the cable. Try the 50 Ohm termination.
>
Arie
>
If the drive is a sine wave, a cable can't generate that 2nd harmonic.
I don't understand how a reflection can account for it either. THe cable's
only 4' long! However, with the 50 ohm input enabled, the 2nd harmonic
disappears. It's just one of those inexplicable mysteries that no one
knows the answer to. :)
If this oscillator is made to drive 50 Ohms and you don't
provide that, internal buffer stages may saturate or do other
weird things. If it works OK *with* the 50 Ohm load, then
your problem is solved, no?
Jeroen Belleman