LogDC (DC Logarithmic Amplifier)
Symbol
Available in ADS
Parameters
Name |
Description |
Units |
Default |
|---|---|---|---|
VoltSlope |
Gradient of transfer characteristic |
V/decade |
1.e-3 |
VoltIntercept |
Vin for zero output |
V |
1.e-3 |
Z1 |
Reference impedance for port 1 |
Ohm |
50 |
Notes/Equations
- LogDC provides an output that is a logarithmic function of the input. If, for example, the scaling is 1 volt/decade, the output changes by 1V for any tenfold increase of the input.
The intercept point is the input level at which the output voltage is 0.
Vout = VoltSlope × log ((Vin / VoltIntercept) + 1) - Several logarithmic amplifiers are available in ADS: LogACDemod, LogDC, LogSuccDetect, and LogTrue. LogACDemod, LogSuccDetect, and LogTrue accept an RF input and generate a DC output voltage proportional to the log of the input voltage. LogDC will accept an RF input but does not generate a DC output.