Amplitude Sweep?

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Amplitude Sweep?

2012-03-19 06:45:31

hello guys,

I am trying to generate Amplitude Sweep Signal, at a given constant frequency with the following equation

X(n) = 10^{(start_amp + Delta.k.t)/20} * Sin(2.pi.f .t) * (1<<24)

but i am not getting exact Amplitude sweep signal, can any one know whats wrong with above formula....

If there exist a better way of generating Amplitude sweep signal with a specific formula, please explain

Thanks in Advance....[/size]

Amplitude Sweep?

Reply #1 – 2012-03-19 20:26:56

Looks like you're on the right track. What are you using for start_amp, Delta and k? What's going wrong?

Amplitude Sweep?

Reply #2 – 2012-03-20 04:28:16

Quote from: Notat on 2012-03-19 20:26:56

Looks like you're on the right track. What are you using for start_amp, Delta and k? What's going wrong?

According to the test stream
start_amp = -120
stop_amp = 0
duration of sweep = 30 sec
Delta.k = (stop_amp - start_amp)/duration of sweep = 120/30 = 4
sampling rate = 48000
and yes bro, i am almost there, but my problem is up-to 2 digits of decimal part the amplitude values are matching with reference and after that they are differing and some( 2 or 3) values in decimal part are entirely differing.

Any thoughts ?

Amplitude Sweep?

Reply #3 – 2012-03-20 13:40:56

Quote from: ksr on 2012-03-19 06:45:31

hello guys,

I am trying to generate Amplitude Sweep Signal, at a given constant frequency with the following equation

Code: [Select]
X(n) = 10^{(start_amp + Delta.k.t)/20} * Sin(2.pi.f .t) * (1<<24)
but i am not getting exact Amplitude sweep signal, can any one know whats wrong with above formula....

If there exist a better way of generating Amplitude sweep signal with a specific formula, please explain

Thanks in Advance....[/size]

You might be expecting too much. The highest amplitude sample points on the waveform of a sweep naturally jump up and down because the sampling frequency does not always line up with the frequency of the generated wave at most points.

Amplitude Sweep?

Reply #4 – 2012-03-21 04:06:31

Quote from: Arnold B. Krueger on 2012-03-20 13:40:56

Quote from: ksr on 2012-03-19 06:45:31
hello guys,

I am trying to generate Amplitude Sweep Signal, at a given constant frequency with the following equation

Code: [Select]
X(n) = 10^{(start_amp + Delta.k.t)/20} * Sin(2.pi.f .t) * (1<<24)
but i am not getting exact Amplitude sweep signal, can any one know whats wrong with above formula....

If there exist a better way of generating Amplitude sweep signal with a specific formula, please explain

Thanks in Advance....[/size]
You might be expecting too much. The highest amplitude sample points on the waveform of a sweep naturally jump up and down because the sampling frequency does not always line up with the frequency of the generated wave at most points.

Thanks bro...can you explain in detail the above concept