Oscilloscope reading

I have bought an oscilloscope for testing my own built kwak clock out. But, i am newbie with the oscilloscope :( I wonder if the signal out of the Kwak clock is good or not? Can you please review the photographs for me?
Thanks a lot,

хостинг фотографий

хостинг картинок bmp

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There seems to be some excessive capacitive load. It might be caused by the probe itself (if the test point is a high impedance out), or inherent to the circuit, or caused by the next stage, or caused by cable capacitance, etc. It is hard to tell without knowing at which point do you measure, and what is the capacitance of your probe.


diyAudio Chief Moderator
Paid Member
2002-10-08 11:31 am
This always made me wonder-how much bandwidth is required to see the pulse train of the clock? This looks like the fundamental and a few harmonics, like an above poster said. For an 11.2896MHz clock, how much bandwidth?

10X. I.e. circa 110MHZ to see the pulse well. Now if there are weird and fast ringings you want to observe in fine fidelity on that pulse, then 20X is even crisper.
According to your advise, i used 10x probes for measuring. Firstly, i have calibrated probes with 1kHz square wave. Then i measured the clock waves in same time at the point no:1 and point no:2 (See the Kwak clock schematic). Channel 1 of the oscilloscope is showing the wave at red point no 2. Channel 2 is showing the wave at red point no 1. Before and after the comparator chip, waves are different looking.
Any comment about the Kwak clock out signal? (CH1)
Thank you

Shematic of Kwak clock:

Calibrated 10x probes:
куда залить картинку

Waves measured with channel 1 (at the top) and channel 2 (at the bottom)
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хостинг изображений
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Is the inverting input of the comparator within the common mode range of the input stage? If you change the pot setting to a DC level that is slightly above gnd does that change the output? I dont know this exact comparator but the o/p ought to switching between 5V and gnd. Maybe you should probe the o/p directly, at pin 8. It seems odd that the o/p is a small 500mV signal.