Automatic retrain method for a full duplex modem having an echo canceller and an equalizer

Abstract

Abstract The retrain method is provided for first and second modems operating at a full duplex data transmission. An echo canceller cancels an echo produced in response to the modulated signal of the modems. An equalizer equalizes waveform distortions produced on a receiving modulated signal transmitted through a transmission line. A demodulator demodulates the receiving modulated signal into the input data. The retrain method comprises the following steps: detection of the deterioration of the receiving modulated signal from said first modem, suspension of the data transmission from said first modem in response to the detection of deterioration and transmitting at least once a first training signal having a predetermined pattern and time period, suspension of the data transmission from said second modem in response to said first training signal and single transmission of a second training signal having a predetermined pattern and time period, and automatically training said automatic equalizers of said first and second modems alone in response to the second and first training signals. This method retrains an automatic equalizer alone if the retrain is necessary only for the equalizer.

Inventors

• 👤 Masayoshi Hiraguchi

Bibliographic Details