Hi Brian,
I presume you're referring to the vertical positioning control and not the horizontal positioning control but I presume the vertical one. I did not notice that made much, if any, difference. I don't fully understand this but I think the waviness is caused by overshoot/undershoot of the beam as it jumps from the trace to the readout. If that's the case, then I would think that different vertical positions of the trace would affect this.
Overall, I think I prefer the GATED setting (draws the readout after the traces); however, at least for the 7704A, there's a switch that selects which B slot drives the readout so one must choose one or the other and I'm pretty sure I'm going to forget that setting when I have just one time-base in the B position which will disable the readout. Maybe not but for now, I'm going to leave it in the GATED position.
Thanks,
Barry - N4BUQ
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----- Original Message -----
From: "Brian via groups.io" <brianas1948@...>
To: "tekscopes" <[email protected]>
Sent: Friday, December 31, 2021 11:26:08 AM
Subject: Re: [TekScopes] 7704A - Noise on sine-wave traces
Hi Barry , I have been watching these postings with interest . One of my 7844's
has this or a remarkably similar problem . There is the wavy / jumping about
readout but in my case it is made worse by using the position control -- did
this happen with yours . I would be pleased to know how similar my case is and
maybe if its not the same there might be suggestions of where the problem might
be .
many thanks in advance for help from anyone reading this
Brian? (UK)
On Friday, 31 December 2021, 17:16:11 GMT, n4buq <n4buq@...> wrote:
Hi Albert,
That works!? I was just hesitant to start changing the settings without knowing
more about what they affect.? Very nice to have the wavy readouts stable.
Thanks,
Barry - N4BUQ
----- Original Message -----
From: "Albert Otten" <aodiversen@...>
To: "tekscopes" <[email protected]>
Sent: Friday, December 31, 2021 6:53:41 AM
Subject: Re: [TekScopes] 7704A - Noise on sine-wave traces
Hi Barry,
For minimizing that wavy readout forget about the signal standardizer.? Display
your signal (calibrator or whatever) at full height (8 div) and the time base
for the most nervous readout. Then rotate R4465 (Vert. Amp.) for the best
setting (most quiet readout).
Note that this setting is also best for your ordinary signal response. If the
result is still unsatisfactory then perhaps a slight readjustment of R4453
might help (but remember the original setting, just in case).
Albert
On Fri, Dec 31, 2021 at 02:13 AM, n4buq wrote:
I see where Table 4-1, Item 3 (Signal Standardizer Calibration Fixture) states
that "Calibrated 7000-series plug-in units with suitable signal sources may be
substituted if lower performance is acceptable."? I just don't quite see where
the instructions outline how to set those up in place of the standardizer -
particularly for low-frequency linearity and/or vertical high-frequency
compensation.
Thanks,
Barry - N4BUQ
----- Original Message -----
From: "n4buq" <n4buq@...>
To: "tekscopes" <[email protected]>
Sent: Thursday, December 30, 2021 5:11:41 PM
Subject: Re: [TekScopes] 7704A - Noise on sine-wave traces
I remember now that this involves adjustment of the LF Compensation.? The
calibration steps for that calls for a standardizer fixture and I don't have
one of those.? Is there a way to make that adjustment without a standardizer
fixture?
