US 6,958,663 B2 · In-band group delay equalizer and distortion compensation amplifier

Abstract

An in-band group delay equalizer is formed in a simple circuit configuration so as to have a flat group delay characteristic over a wide frequency band without having a peak of group delay near each passband edge. The in-band group delay equalizer includes a plurality of convex group delay circuits. Each convex group delay circuit is formed of one hybrid coupler and two resonators connected to respective divided output ports of the hybrid coupler. The center frequencies of the respective convex group delay circuits are set to be different from each other so that the overall group delay characteristic of the in-band group delay equalizer becomes flat. The bandwidth and the group delay can be easily adjusted. A distortion compensation amplifier with very low distortion can be realized using such an in-band group delay equalizer.

Claims6

Dependent claims

An in-band group delay equalizer for receiving an input signal, the equalizer comprising three or more convex group delay circuits, each having convex group delay characteristic in which a delay time decreases with deviation of frequency from a center frequency, wherein

the center frequency of each convex group delay circuit is different from each others,
the convex group delay circuits are connected in cascade, and
the group delay time of a first convex group delay circuit having a highest center frequency of the three or more convex group delay circuits and the group delay time of a second convex group delay circuit having a lowest center frequency of the three or more convex group delay circuits are greater than the group delay time of the other convex group delay circuits of the three or more convex group delay circuits.

Dependencies are inferred from the claim text.

In-band group delay equalizer and distortion compensation amplifier

Life of this patent

In-band group delay equalizer and distortion compensation amplifier

Life of this patent

Abstract

Claims6