When you use AD8338's AGC function(connecting DETO pin with GAIN and connecting MODE with GND ),will AM signal's modulating signal be inhibited.Should I insert a low pass filter between DETO and GAIN to avoid this。
Apologies for this late response.
The AGC function of AD8338 works in the way that the device will output an RMS voltage corresponding to the absolute value of the difference in voltage between Pin VAGC and Pin VREF (1.5 V). Thus, Vout (rms) = [VAGC-VREF]. This output characteristic of the AGC Circuit function is shown in Figure 45 of the datasheet.
To site an example, here are some output rms of AD8338 with corresponding applied voltage on the VGAC Pin.
a. VAGC = 1.0 V
b. VAGC = 1.2 V
c. VAGC = 2.2 V
I'm just curious, by AM signal you are planning to drive the VAGC pin with an AC voltage instead of DC right?
Thank you for reply.
I think I unsuccessfully convey my opinion. I just want to know could AD8338's AGC function used for AM signal. Because compared with FM signal，AM signal have amplitude information, I'm worried about that if you sent AM signal into AD8338, the output may be become sinusoidal wave at frequency of carrier of AM. Because the change of amplitude modulating signal disappear because of the AGC function。
I think this question is already under discussion in this thread AD8338 AGC function for AM signal.
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