These videos are great. To somebody like me who has no electrical engineering education, being able to see somebody walk through the concepts like this is a great substitute for practical experience. It turns the previously completely abstract concepts into something tangible and real; thanks!
You need to insure the flip-flops start running from a known input state by bringing them out of reset (clear) when starting the oscillator. Otherwise, your oscillator might startup with the Q signal leading the I signal.
Awesome videos. Keep them coming. I haven't seen Jim Williams style circuit boards in a while. I want to make my own now. I'm quite experienced with analog design but I still found the videos useful.
Another option is to use one XOR gate to convert Q and the clock to Grayscale. But, a dual flip flop does have the advantage of requiring only one chip when discrete components are used.
could you also do a video detailing the requirements for the op-amps on the output capacitors of the mixer? so specifically you have 4 identical capacitors on the output of the analogue switches, i notice the inverting and non-inverting often have different impedances and RC combinations... is one side intentionally a more aggressive low pass filter than the other? and for what purpose?
Btw. what I like to do instead of these bnc to scope probe adapter to scope probe things on prototypes (and sometimes on final boards too) is simply two wire spirals that exactly fit the diameter of the scope tip and solder that directly to the board. I have looked and found a video that explains this in more detail: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE--4q8geE5ef8.html
+Dennis Lubert Also an excellent solution! The late great Bob Pease did a good video on that too: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-2vzvWUqUtb8.html
You shouldn't run arbitrary waveforms into that digital logic chip. Even though it uses TTL logic levels it's likely a CMOS chip so it has time limits for how long you can be in the region where it's not clearly high or low. If you stay in that region for too long, it causes "shoot through" and can make the chip unstable. This is especially true for chips with memory like this D flip flop. If you read the data sheet you'll see recommended ns/V transition times. To get around this you need to use a chip with Schmitt Trigger inputs or add a schmitt trigger buffer before you run the signal into the chip. Great video otherwise, love your videos.
The square outputs have tons of harmonics. Aren't they going to bring havoc to the output of the mixer? Or you are planning to filter them before sending to the mixer?
With this type of oscillator i can generate a full 0-359° phase-shift, right? I mean, if you balance modulate the real and imaginary bytes you should get a nice QAM constellation depending on the levels you are using. For eight bit each channels i have 256 bits of different levels (with r-2r ladder DAC) and so it can provide 256 different phase and 256 different amplitude. Am i right or not?
+Daniel von Hofbräuhaus Well maybe not really 256 different of each but you get the idea. I tested it with math an graphs and it seems it is working like it.
Yes, once you add the quadrature signals you can change the phase of the sum by changing the amplitude of the quadrature signals. +w2aew has some excellent videos demonstrating just that: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-h_7d-m1ehoY.html ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-5GGD99Qi1PA.html
devttys0 Great video, One video Request:- I have seen many videos online explaining what is bode plot but non of them have taken an unstable circuit and walk through every step how to compensate it ? Can you make videos on op-amp based and how to know if my circuit is going to oscillate and finding out what we need to make it stable using bode plot be it using some software ?
