Patent ID: 6356131
Filing Date: 2002-03-12
Classification: H03H

Abstract:
A 90-degree phase shifter comprising:an input terminal, a first output terminal, and a second output terminal; a first variable gain amplifying means, a first phase adjusting means and a low pass filter means, which are cascaded between said input terminal and said first output terminal; a second variable gain amplifying means, a second phase adjusting means and a high pass filter means, which are cascaded between said input terminal and said second output terminal; a phase error detection means receiving a first output signal on said first output terminal and a second output signal on said second output terminal for detecting a phase error between said first output signal and said second output signal to supply a first phase adjusting signal and a second phase adjusting signal to said first phase adjusting means and said second phase adjusting means, respectively; and an amplitude error detection means receiving said first output signal and said second output signal for detecting an amplitude error between said first output signal and said second output signal to supply a first gain control signal and a second gain control signal to said first variable gain amplifying means and said second variable gain amplifying means, respectively, whereby said phase error and said amplitude error between said first output signal and said second output signal are removed independently of each other.