01 July 2021

Testing the equipment by testing other things

I found myself stuck in a testing loop while learning on-the-field how to use the Hantek oscilloscope: I was creating test cases for the oscilloscope that dubbed into test cases for accessories.

See this. The scope has a -3dB 150 MHz bandwidth, so I picked up my 14 MHz Marker Generator and tried to visualise the output terminated on a 50 ohm dummy load. The marker generator creates a short impulse in the time domain, which results in many peaks in the frequency domain. The short square impulse should be 10 ns long inside a period T of 71 ns at 14 MHz.

Grab all the probes in the lab and see which one renders better the impulse train. Don't forget to set the probe to 10x.

Probes were tested in this order:

  1. P6100, 100 MHz
  2. P6100, 100 MHz
  3. PK-8150, 150 MHz
  4. PP150B 150 MHz, Hantek
  5. 88025, 250 MHz, Greenpar

The first stitch below shows 4 periods of the test signal, while the second image is a zoom-in on one impulse.

According to the screenshots (wow!), all five probes behave almost in the same way! Even the input square wave show ringing.

Well, I do want to see an impulse train so I will either change the XTAL in the marker generator or use the arbitrary function generator embedded into the scope. Or both.

When time allows I will repeat the experiment with a 200 MHz Siglent oscilloscope (not mine).