How to generate a signal

[celynn]

Hi, Can anyone tell me how to generate this signal.

i want to generate a simple signal at amplitude 1 with 4096 samples to pass through my FFT.

The purpose is to check the algorithms.

Message Edited by celynn on 10-21-2005 12:18 PM

Message Edited by celynn on 10-21-2005 12:19 PM

[Dennis_Knutson]

The VI you posted does generate a signal. In the example, you've requested 40960 samples and not 4096.

[celynn]

Hi , my mistake i want to generate 40960 of samples.

Bascially my actual signal have 40960 discrete samples so i want to generate a signal to pass through my vi.

How much must my "sampling frequency" in the generate signal be?

[Dennis_Knutson]

If your actual signal has 40960 samples, over what time was that acquired? If you're trying to simulate something you've captured with a DAQ board, then you should know what the sampling rate of the acquisition was.

[celynn]

Hi

precisely i have no idea what is the sampling rate of the signal. I just want to generate the signal with constant amplitude based on the actual sampled signal. is it possible to achieve?.

Attached is my actual sampled signal.

[Dennis_Knutson]

I really don't understand what you're trying to accomplish. The Generate Sine Waveform example you using will generate a 1 Hz sine wave sampled at 1000 samples/sec. You specify 40960 samples so that means about 50 seconds (40960/1000) worth of data or nearly 50 complete cycles. If you want one complete waveform with 40960 samples, then set your sample rate equal to the number of samples. If you want a constant amplitude, don't generate a sine wave. Just use the initialize array and wire the constant to the value input and the number of samples to the dimesnion size input.

[celynn]

Hi, i have found out the sampling rate of my signals is at 4096Hz.

Therefore i generate 3 signals, 2 sine wave and 1 cos wave at Fs=4096Hz and #s=40960 and pass through my vi.

I am trying to achieve a multiple coherence of all 1 from 0Hz to 500Hz.

Attached plot is what i get from the output.

Do you know where went wrong?

[celynn]

I make a mistake by saying the signal generated fs was at 4096 because when i pass the generated signals at fs= 4096 it give an error to calculate the coherence. Therefore i change the fs to 1000Hz . Attached is the plot.