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VCA810: Amplitude control of sinusoidal signal

Leonardo Marrone
Prodigy 20 points
Part Number: VCA810
Other Parts Discussed in Thread: VCA822

Dear all,

I need to control the amplitude of a sinusoidal signal with frequency between 0 and 1 kHz and amplitude 1V. I am guessing to use the VCA810 with a voltage analog input  0 - 5V.

1) Can this device affect somehow the frequency? I wish the frequency doesn't change

2) Is the range of frequency to low for apply the VCA810? In case it is, could you suggest other op-amps?

Thank  you

Leonardo Marrone

  • 0
    Guru 48155 points
    Morning Leonardo,

    The VCA810 is a large adjust range VCA kind of more intended for pulse amplitude adjustment as it has very poor HD performance.

    You question about changing frequency maybe relates to propogation delay? The VCA cannot change the output frequency (unless you are rapidly modulating the control input - and then you are mixing). It can add a phase delay and create more harmonics.

    If you don't care about harmonics being generated (or HD) then yes the VCA810 is fine.

    You might also look at the VCA822 for lower HD and a 40dB range - it is diff input to single out, but you can drive it single ended.
  • 0 in reply to Michael Steffes
    Guru 48155 points
    And yes, these parts might seem really fast for your signal, but I am not aware of similar parts in lower speed ranges.