## Topic: Amplitude Sweep? (Read 1898 times)previous topic - next topic

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• ksr
Amplitude Sweep?
##### 19 March, 2012, 02:45:31 AM
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

• Notat
Amplitude Sweep?
##### Reply #1 – 19 March, 2012, 04:26:56 PM
Looks like you're on the right track. What are you using for start_amp, Delta and k? What's going wrong?

• ksr
Amplitude Sweep?
##### Reply #2 – 20 March, 2012, 12:28:16 AM
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 – 20 March, 2012, 09:40:56 AM
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

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.

• ksr
Amplitude Sweep?
##### Reply #4 – 21 March, 2012, 12:06:31 AM
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