Chapter 9 Communications Circuits Power or Amplitude Voiceband Upstream Downstream Band Band Frequency 4 kHz 2.2 MHZ Figure 9-5 An ADSL circuit is divided into several channels, and uses a much wider frequency range than a standard telephone circuit. www.gxmu.edu.cnFigure 9-5 An ADSL circuit is divided into several channels, and uses a much wider frequency range than a standard telephone circuit. www.gxmu.edu.cn Chapter 9 Communications Circuits