Instructables

Is it possible to homothetically dilate a signal?

Imagine I have a very short signal that I would like to observe, however the frequency is too high for simply viewing it on an oscilloscope. Is there any possible way to "dilate" it over time? Obviously, I am not talking anything digital, probably some crystal retranslation... 
Somehow, I haven't managed to find anything using the most obvious way (googling), but, probably, I don't know how to.

Is this a burst, or a single pulse ?
gruffalo child (author)  steveastrouk1 year ago
A single pulse. Actually, the new idea is to forget about the exact shape and get something proportional to the amplitude from an RC chain and then amplify it.
That will only work if the output impedance of the source pulse is very very low, or you will struggle. Try using a sample and hold chip ; you can always gate the device with the pulse
how high a frequency and what kind of signal sine, saw, square, or triangle?
Well, that problem should arise at something close to the clock rate of computers/microcontrollers, and it's just some signal - no particular shape, it's what I want to look at.
If you don’t care about the shape a frequency counter is all you need.

There are only two things you can do to view extremely high frequencies, use components with a shorter transition time making the electronics faster for higher frequencies or make the signal longer.

If you make the signal longer the shape of the signal is very important.

It confirms the duty cycle of a square wave.

It tells you if the amplifier you built amplifies the signal properly or full of feedback signals.

It tells you if the oscillator you just built produces a sine square or triangle wave.

That is what viewing the signal with an oscilloscope and other devices is for, otherwise it serves no purpose.

In truth a square wave is a trapezoid take the transition time for a gate let’s say it is 4 peako seconds so the minim time for the gate to effect another gate is 6 peako seconds and a full wave is 12 peako seconds at a 50% duty cycle or 83 GHz.

One of the uses of viewing a signal is to observe the transition time if a components transition time is longer than the duty cycle of the signal applied to the component the signal never gets past the component.

The same thing happens when you look at a flashing LED up to a certain speed and duty cycle you can see the LED flashing faster than that and the LED looks like it is just on. With electronic devices a device may see a signal of a high enough frequency as a DC voltage.

If the shape is not important you can just use a frequency divider to make the signal longer however it won’t retain its shape or duty cycle. It can turn a sine wave into a square wave and it can turn a 33% duty cycle square wave into a 50% duty cycle.

A frequency attenuator may work well with a sine, a triangle, and the duty cycle of a square wave however it can change the transition time of a square wave.

So yes the signal shape is as important as why you want to view it.

One-shot pulses would be observed on a storage scope.