A 2-GHz Gain Equalizer for Analog Signal Transmission Using Feedforward Compensation by a Low-Pass Filter

A 2GHz gain equalizer for analog signal transmission using a novel gain compensation method is described in this paper. This method is based on feedforward compensation by a low-pass filter, which improves the gain-equalizing performance by subtracting low-pass filtered signals from the directly passed signal at the end of a transmission line. The advantage of the proposed method over the conventional one is that the gain is equalized with a smaller THD at higher frequencies by using a low-pass instead of a high-pass filter. In this circuit, the peak gain is adjustable from 0 to 2.4dB and the frequency of the peak gain can be controlled up to 2GHz by varying the value of an external capacitor. Also this circuit achieves THD with 5dB better than the conventional circuits.