| 摘要 |
A high-frequency RMS-DC converter having extended dynamic range operates by dynamically at low cost by adjusting the scaling factor (denominator) of a detector cell such as a squaring cell. The output from the squaring cell is averaged to generate a final output signal which can be fed back to a scaling input for operation in a measurement mode, or used to drive a power amplifier in a controller mode. By implementing the squaring cell as a transconductance cell using a modified multi-tanh structure, the scaling factor can be adjusted by dynamically changing the tail current through the cell which, in the measurement mode, is achieved by connecting the averaged output back to the squaring cell. An exponentially responding amplifier can be used in the feedback loop to provide a linear-in-dB output characteristic.
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