Patent ID: 8312496
Filing Date: 2012-11-13
Classification: H04N

Abstract:
1. A method for measuring a frequency response between a first test point and a second test point of a cable television (CATV) network comprising: a head end for generating and receiving modulated digital signals, wherein each said modulated digital signal occupies a pre-defined frequency band; and a cable plant for propagating said modulated digital signals, wherein a cable modem is operationally coupled to the first test point, the method comprising: (a) injecting, at the first test point, a test signal having an amplitude and a first frequency, wherein the injecting of the test signal occurs during a transmission time slot allocated by the head end for the modem to transmit a signal to the head end; (b) receiving the test signal at the second test point during a reception time slot that is delayed relative to the transmission time slot by a time of propagation of the test signal between the first and the second test points of the CATV network; (c) measuring the amplitude of the test signal at the second test point during the reception time slot; (d) dividing the amplitude of the received signal by the amplitude of the injected signal, so as to obtain the frequency response of the CATV network between the first and the second test points at the first frequency; and (e) repeating steps (a) to (d) at a second frequency different from the first frequency, so as to obtain the frequency response of the CATV network between the first and the second test points at the second frequency.