obtain FSK/PSK modulation real time signal

[Serina]

Hi everyone,

                   I am trying to obtain a amplitude-time waveform for FSK and PSK modulation on my scope. Is it possible? I have succeeded in getting the waveform for AM, FM & ASK modulation only. I am using Agilent Technology E4438C 250kHz-6.0GHz ESG VECTOR Signal Generator and oscilloscope is Hewlett Packard 54600B 100MHz.

[chris_amadasun]

Hello
How are you obtaining the graphs for your ASK, AM and FM modulations?
Since FSK and PSK are also modulation schemes if they are displayed on your Oscilloscope you should be
able to transfer it to you PC the same way you did with the others.

Let us know if you have any further questions.

[Serina]

Hi,

    i obtained those modulation by adjusting the setting or measurement scales on the scope and signal generator. But i am taught by my project supervisor. However, i could not obtain the modulation i had mentioned in my 1st message because we are not sure in how to adjust and what will the signal waveform should look like? My supervisor say if worse come to worst situation at least i must find a picture of the modulation so she can observe and study how to adjust using the scope and signal generator to produce the waveform out. My objective is to produce/obtain a real time signal under the same measurement with the internal generate exercise similarly. For example, AM modulation frequency is 750 kHz in the LabView exercise; when i set the same measurement in signal generator/scope and correct scales i will produce a similar real timesignal waveform same as the Internal generate waveform. If you have Labview software and those instrument will be best but i have the pic you can see whether you understand anot.. Thanks!

[chris_amadasun]

Hello,
There are no direct vi's that will give you FSK and PSK with the function generator you are using.
In PSK the data is encoded in the phase of the carrier, the image will look like this.
All you need to do for PSK is multiply a carrier signal with the output of a random sequence generator.

For FSK the output of a random sequence generator is applied as the input of a Voltage Controlled Oscillator (VCO),
the output will look like this.

The ability to perform this modulation schemes in LabVIEW will depend upon the devices you are using, you might
consider reading through the manuals of your devices to discover if those schemes are supported.

[lahorimunda]

Hi,

    I want to know how did you obtain a ASK modulation. I want to generate an ASK voltage output but I have no idea how to do it in Labwindows CVI. Can you refer some example.