If there’s an application where a good old analogue oscilloscope will deliver right away, it’ll have to be the classical #hamradio two-tone modulation test 😃

Using the #Cutegen™️ and a resistive mixer, I’m modulating a #yaesuft817 with two tones: 700 and 1900Hz, observing the resulting RF signal on a spectrum analyzer and the oscilloscope.

A simple and traditional way to detect unlinearities and observe transmitter performance. And it’s an absolutely beautiful picture on the oscilloscope screen ☺️❤️

All time RF engineering and #hamr classic 🙂

#signalsaturday #testandmeasurement #rfengineering #rfengineer #electronics #electronicsengineering

I found a small speaker and attached a square of reflector tape onto the dome.

Using the #CuteGen™️ I sent 1Vpp, 40Hz, to the speaker. No sound, which really isn’t a surprise because it hardly has any response at such low frequencies.

On the scope however, a funny curve appeared 😃

The top sine wave is the speaker drive signal, the lower yellow trace is the output from the laser amplifier (see my other post, building the circuit).
There’s a clear marking at the top and bottom of the sine wave. Between them, a sawtooth-like response. Each of the sawtooth peaks means the speaker surface moved a whole wavelength, in this case 650nm. 4-5 of those means that the speaker moves about 3um (micro meter) in each direction.
Not much 😳🤯

No wonder there’s no audible sound 👌🏻

It took a while for me to adjust it all to produce this measurement. But it does work 😎

#physics #stemeducation #stem #electronics #electronicsengineering #testandmeasurement #uni-t #rohdeschwarz #laser #funwithlasers

It’s #waveformwednesday, let’s make it #vintagewednesday as well 👴🏻😃

I’m assembling a small low pass filter and I want to sweep it from 100Hz to 10kHz. Let’s do it the old fashioned way ☺️

Before modern oscilloscopes with BodePlot options became available for everyone, a common and quick way to sweep a circuits frequency response, was to connect an external sweep generator and look at the resulting curve on the screen.

Using the #CuteGen™️ I’m sweeping logarithmic from 100Hz to 10kHz. I’m using the generator trigger output as trigger on channel 2 and the X-axis is adjusted to be exactly one period, i.e. 100-10KHz.

The filter response can clearly be seen 🙂

This method still has its justification. Not everyone has fancy scopes and even if they have, it’s still a smart and fast way to quickly observe a frequency response. Show me any fancy scope updating a bode plot every 100ms 👌🏻🙂

#testandmeasurement #hamr #hamradio #rfengineering #rfengineer #electronics #electronicsengineering

It’s #signalsaturday and I’m continuing the #CuteGen™️ test series by looking a bit at the harmonics 🙂 How clean is it?

Starting at 1kHz I’m using my #Siglent #oscilloscopes powerful FFT functionality and with harmonics >60dB down, this little thing really is a decent audio function generator.

I then moved to the spectrum analyzer and did some tests at (much) higher frequencies. Only included 10 and 30MHz here, but pattern is clear: harmonics are generally nicely attenuated, more than 60dB, although at the high end, it’s not quite that much, more like 50dB and a sub-carrier spur appeared as well. Makes me wonder how well the 60MHz version performs 🤔

#testandmeasurement #rfengineering #rfengineer #electronics #electronicsengineering #uni-t #hamradio #hamr