Method for reducing HRC mode reception time in cable television

In a video signal receiver without a CATV mode selection switch, a method for reducing HRC mode reception time comprising:

• an initial step comprising transmitting to a tuner a modulation frequency corresponding to a selected channel and determining the presence of a video synchronizing signal using a system control microprocessor when a channel has been selected;
• a first normal signal reception step, executed when the synchronizing signal is detected in said initial step and an output state of an AFT port is high, comprising monitoring the AFT port while stepwise increasing the modulation frequency either until an increased portion reaches a given limit, or until the output state of the AFT port changes to low, and, as soon as the output state of the AFT port changes to low, stopping the stepwise increase of modulation frequency and commencing reception of normal signals broadcast in standard mode;
• a second normal signal reception step, executed when the synchronizing signal is detected in said initial step and the output state of the AFT port is low, comprising monitoring the AFT port while stepwise decreasing the modulation frequency either until a decreased portion reaches a given limit, or until the output state of the AFT port changes to high, and, as soon as the output state of the AFT port changes to high, stopping the stepwise decrease of modulation frequency and commencing reception of normal signals broadcast in standard mode;
• a third normal signal reception step, executed when the synchronizing signal is not detected in said initial step and the output state of the AFT port is high, comprising transmitting an adjusted modulation frequency, monitoring the AFT port while stepwise increasing the adjusted modulation frequency either until the increased portion reaches a given limit or until the output state of the AFT port changes to low, and, as soon as the output state of the AFT port changes to low, stopping the stepwise increase of the adjusted modulation frequency and commencing reception of normal signals broadcast in HRC mode;
• and
• a fourth normal signal reception step, executed when the synchronizing signal is not detected in said initial step, and the output state of the AFT port is low, comprising transmitting the adjusted modulation frequency, monitoring the AFT port while stepwise decreasing the adjusted modulation frequency either until the decreased portion reaches a given limit or until the output state of the AFT port changes to high, and, as soon as the output state of the AFT port changes to high, stopping the stepwise decrease of the adjusted modulation frequency and commencing reception of normal signals broadcast in HRC mode.