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Amplitude Sweep?, the equation for generating amplitude sweep
ksr
post Mar 19 2012, 07:45
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hello guys,

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

CODE
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....

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Notat
post Mar 19 2012, 21:26
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Looks like you're on the right track. What are you using for start_amp, Delta and k? What's going wrong?
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ksr
post Mar 20 2012, 05:28
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QUOTE (Notat @ Mar 20 2012, 01:56) *
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 ?

This post has been edited by ksr: Mar 20 2012, 05:49
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Arnold B. Kruege...
post Mar 20 2012, 14:40
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QUOTE (ksr @ Mar 19 2012, 02:45) *
hello guys,

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

CODE
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....



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.
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ksr
post Mar 21 2012, 05:06
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QUOTE (Arnold B. Krueger @ Mar 20 2012, 19:10) *
QUOTE (ksr @ Mar 19 2012, 02:45) *
hello guys,

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

CODE
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....



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 ????
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