how to display high frequency on a PC

[saurabh17g]

I have a 12MHz wave received from a circuit. I want to display it on PC.
Pls giv me some ideas about it.

Problem: This 12Mhz signal has to pass through a micro-controller and micro-controller will tell PC using RS232 about the waveform.
But microcontroller works on 1Mhz and due to interfacing and other stuff, the signal through ADC comming to microcontroller can' t exceed 10 to 100kHz.
So is there any other way to do this?

 

[blueroomelectronics]

Which microcontroller are you using?

 

[Nigel Goodwin]

It's really very unclear what you're wanting to do?.

Assuming it's create a PC oscilloscope you essentially have to make an entire storage scope (minus the screen) and then transfer the data (not in real time) to the PC to display it. There have been many such projects done by University students, and you can find them all over the Internet - most use FPGA's or similar.

 

[saurabh17g]

@blueroomelectronics
I m using AVR atmega32 microcontroller

@Nigel Goodwin
I want to display 2 sinewaves of high frequency(as stated above around 12 Mhz) on the PC and calculate the phase difference between the two.

 

[Nigel Goodwin]

You're not going to do that in that way..

 

[Hero999]

Why not use a frequency counter or a 'scope?

 

[Thunderchild]

can't you do that using some sort of circuit that will detect the difference in voltage between the two and work out the phase ? I uC might work for that but you need almost simultaneous sampling of both signals, or if the signal is of known voltage and frequency, For any displaying you will really be better off with a proper oscilloscope, if you just after the figure there may be other ways ?

 

[Hero999]

You need two channel PC oscilloscope or two single PC oscilloscopes which can be stacked.

Tiny USB Oscillocsope

 

[saurabh17g]

@Nigel Goodwin
then how to do it?
@hero999
frequency counter will give me the frequency but would not be able to compare 2 different waveforms with different phases.
what do u mean by 'scope?
@Thunderchild
phase diff producing ics ad9901 , 8302 are there. but they are not suitable for the requirement bcos we need phase diff along with the display of signals on PC.


one more thing:
I am planning to use PC audio card (stereo input) and display waveform using Matlab software. any suggestions for this?
Now, there is a problem.
Amplification of the received wave:
High freq opamp is necessary. this is bcos IC741, 0p07 will work for signals upto 1mhz. suggest me some better opamp ic.
second:
I have only one audio port in my PC. so when 2nd waveform comes, it will get combined with the first bcos of single wire. so how to solve this problem?

 

[Gobbledok]

... will tell PC using RS232 about the waveform.

...I am planning to use PC audio card (stereo input)

Which one is it? Your PC audio card certainly won't measure up to 12MHz.

Not a simple project and you should just buy a PC based oscilloscope as has been suggested.

 

[Nigel Goodwin]

@Nigel Goodwin
then how to do it?

As I said earlier, to do it in that way requires building an entire storage scope and just using the PC as it's display.

Why not generate a phase difference signal externally and measure that?.

 

[xpi0t0s]

You can't measure a 12MHz signal with a 1MHz PIC. Can't be done. Imagine you can catch tennis balls at the rate of one per second. Now imagine some twit loads up a ball shooter and switches it to 100 shots per second.

If you squirt each signal into a divider for which you know the dividing ratio, e.g. 256, then you will get at the output a 12MHz/256=46875Hz signal, which you can count with a PIC, and multiply the resulting frequency by 256 to calculate the original frequency.

That won't help much with the phase difference. Just playing with ideas, if you XOR the output of the two dividers together that will give a short pulse at each end; if you feed that into an RC network then you might be able to measure the rise and fall times, from which you might be able to deduce the pulse width and therefore the phase difference.

 

[saurabh17g]

if phase difference was the only criterion, i was almost done with the project as ics AD 9901 and ad8302 was sufficient for my application. but the requirement is that they want actual waveform to be stored so that they will be able to print it out and put it in some journal. Now, on the top of it, they are demanding wireless application.

earlier requirement:
generation of 10Mhz frequency.
passing it into sample and getting the received freq .
displaying both the waveforms on PC.
computer software to calcuate phase difference
New requirement:
A remote controlled equipment to indicate the frequency.
once the frequency count is received , a circuit has to generate the frequency.
This frequency is to be passed thru sample and a received frequency is to be stored.
Both the transmitted and received frequencies are to be stored and given to PC for display.