I just started using my QA403. When measuring the QA403 output on an analog voltmeter (HP and Kenwood) the meter is very unstable, like it’s oscillating somewhat. The QA403 measures fine and shows no instability. These measurements are one channel, single ended, only one cable is used and the other output is not terminated.
With other analog sources these meters are working without instability, for example with Trio and Instek analog signal generators, as well as with my “Victor” 1KHz. generator.
The QA403 USB voltage shows approx. 4.7 Volt. The instability seems to be affected by the sample rate (48 kHz., etc.. The higher the sample rate the lower the instability.
I can understand that. I will have to use the QA403 with an external oscillator. Other - analog - equipment that I use for measurements shows useless results with the QA403 bursts. I use analog voltmeters, scopes, wattmeters and of course speakers. With bursts I get I get garbare in, garbage out. If I had known this prior to purchasing the QA403 I don’t think I would have purchased one. I know about future developments in this area, so I can only hope it’s worth waiting.
Hi @Gerrittube, just hit the letter “I” (eye) when you want a constant signal. Do whatever measurement/analysis you need with the QA403, and when you want to sanity check, switch to continuous mode and double check everything. I think you’ll find bit by bit that your other instruments will get used less and less. And if you really need concurrent measurements, just dial in a larger FFT. for example, a 256k FFT at 48K will give a burst that last 5 seconds, plenty of time for your DVM and watt meter to lock in and settle.
Hi Matt, I appreciate your response. I understand hitting “I” enables Idle mode. When measuring (with Run) nothing changes when I hit “I“. The output still bounces up and down, nothing changed. Furtunately my external generators will do the the job for now. When measuring changing voltages and power I still prefer “old style” analog meters. Designing and testing amplifiers with variable settings works better using analog meters, changes are easier to monitor. Once the amplifier design finalizes, the QA403 does a fine job.
