CATV RETURN BAND SWEEPING USING DATA OVER CABLE SERVICE INTERFACE SPECIFICATION CARRIER

摘要

The existing Data Over Cable Service Interface Specification (DOCSIS) carriers generated by field test equipment or by the CATV subscriber modems are used to determine the amplitude response of the return band in a CATV system.

主权项

1. A method for determining the linearity of a CATV return band comprising:
permitting a cable modem to log in to a Cable Modem Termination System (CMTS); determining the transmit carrier frequency, symbol rate, and level for each active carrier in the return band; determining the transmit carrier ranging error level for each active carrier in the return band; determining the transmit carrier pre-equalizer filter coefficients for each active carrier in the return band; adjusting each active return band carrier level by its ranging error and determining the average transmit level; determining the in-channel response for each active carrier in the return band; and, generating a return band frequency response.