Monitoring system for TV, cable and VCR

Claim 1

A method of monitoring the usage of a video monitoring system that includes a video monitoring device, a cable converter and a VCR, said cable converter having an output terminal that is selectively connected to an input terminal of said VCR, the method comprising the steps of: determining by means of a monitoring device whether said output terminal of said cable converter is connected to said input terminal of said VCR; if it is determined that said output terminal of said cable converter is connected to said input terminal of said VCR, supplying a first channel detection signal from said monitoring device to an input terminal of said cable converter while varying a frequency of said first channel detection signal, receiving by means of said monitoring device a signal output from an output terminal of said VCR, determining by means of said monitoring device whether said first channel detection signal supplied to said input terminal of said cable converter is present in said signal output from said output terminal of said VCR, and if so, detecting by means of said monitoring device which of a first plurality of channels has been selected by said cable converter on the basis of the frequency of said first channel detection signal that is present in said signal output from said output terminal of said VCR; and if it is determined that said output terminal of said cable converter is not connected to said input terminal of said VCR, supplying a second channel detection signal from said monitoring device to said input terminal of said VCR while varying a frequency of said second channel detection signal, receiving by means of said monitoring device a signal output from said VCR, determining by means of said monitoring device whether said second channel detection signal is present in said signal output from said VCR, and if so, detecting by means of said monitoring deyice which of a second plurality of channels has been selected for reception by said VCR on the basis of the frequency of said second channel detection signal that is present in said signal output from said VCR.

Claim 2

A method of monitoring the usage of a video monitoring system that includes a video monitoring device, a cable converter and a VCR, said cable converter having an output terminal that is selectively connected to an input terminal of said VCR, the method comprising the steps of: determining by means of a monitoring device whether said output terminal of said cable converter is connected to said input terminal of said VCR; if it is determined that said output terminal of said cable converter is connected to said input terminal of said VCR, supplying a first channel detection signal from said monitoring device to an input terminal of said cable converter while varying a frequency of said first channel detection signal, receiving by means of said monitoring device a signal output from an output terminal of said VCR, determining by means of said monitoring device whether said first channel detection signal supplied to said input terminal of said cable converter is present in said signal output from said output terminal of said VCR, and if so, detecting by means of said monitoring device which of a first plurality of channels has been selected by said cable converter on the basis of the frequency of said first channel detection signal that is present in said signal output from said output terminal of said VCR; and if it is determined that said output terminal of said cable converter is not connected to said input terminal of said VCR, supplying a second channel detection signal from said monitoring device to said input terminal of said VCR while varying a frequency of said second channel detection signal, receiving by means of said monitoring device a signal output from said VCR, determining by means of said monitoring device whether said second channel detection signal is present in said signal output from said VCR, and if so, detecting by means of said monitoring deyice which of a second plurality of channels has been selected for reception by said VCR on the basis of the frequency of said second channel detection signal that is present in said signal output from said VCR.

Claim 8

An apparatus for monitoring the usage of a video monitoring system that includes a video monitoring device, a cable converter and a VCR, the apparatus comprising: means for selectively connecting an output terminal of said cable converter to an input terminal of said VCR; means for supplying a first channel detection signal to an input terminal of said cable converter while varying a frequency of said first channel detection signal when said output terminal of said cable converted is connected to said input terminal of said VCR; means for receiving a signal output from an output terminal of said VCR; means connected to said means for receiving for detecting that said first channel detection signal is present in said signal output from said output terminal of said VCR and for determining which of a plurality of channels has been selected by said cable converter on the basis of the frequency of said first channel detection signal that was detected in said signal output from said output terminal of said VCR; means for supplying a second channel detection signal to said input terminal of said VCR while varying a frequency of said second channel detection signal when said output terminal of said cable converter is not connected to said input terminal of said VCR; and means connected to said means for receiving for detecting that said second channel detection signal is present in said signal output from said output terminal of said VCR and for determining which of a second plurality of channels has been selected for reception by said VCR on the basis of the frequency of said second channel detection signal that was detected in said signal output from said output terminal of said VCR.

Claim 9

An apparatus for monitoring the usage of a video monitoring system that includes a video monitoring device, a cable converter and a VCR, the apparatus comprising: means for selectively connecting an output terminal of said cable converter to an input terminal of said VCR; means for supplying a first channel detection signal to an input terminal of said cable converter while varying a frequency of said first channel detection signal when said output terminal of said cable converted is connected to said input terminal of said VCR; means for receiving a signal output from an output terminal of said VCR; means connected to said means for receiving for detecting that said first channel detection signal is present in said signal output from said output terminal of said VCR and for determining which of a plurality of channels has been selected by said cable converter on the basis of the frequency of said first channel detection signal that was detected in said signal output from said output terminal of said VCR; means for supplying a second channel detection signal to said input terminal of said VCR while varying a frequency of said second channel detection signal when said output terminal of said cable converter is not connected to said input terminal of said VCR; and means connected to said means for receiving for detecting that said second channel detection signal is present in said signal output from said output terminal of said VCR and for determining which of a second plurality of channels has been selected for reception by said VCR on the basis of the frequency of said second channel detection signal that was detected in said signal output from said output terminal of said VCR.

Claim 16

A method of monitoring usage of a video monitoring system that includes a video monitoring device and a VCR, the method comprising the steps of: supplying a channel detection signal to an input terminal of said VCR; detecting that said channel detection signal is present in a signal outputted from an output terminal of said VCR and determining to which channel said VCR is tuned; and supplying a channel identification signal from said monitoring device to an RF input of said VCR, said channel identification signal including data that identifies said detected channel and being recorded on a magnetic tape by said VCR to identify a source of a program signal recorded on said magnetic tape with said channel identification signal.

Claim 17

A method of monitoring usage of a video monitoring system that includes a video monitoring device and a VCR, the method comprising the steps of: supplying a channel detection signal to an input terminal of said VCR; detecting that said channel detection signal is present in a signal outputted from an output terminal of said VCR and determining to which channel said VCR is tuned; and supplying a channel identification signal from said monitoring device to an RF input of said VCR, said channel identification signal including data that identifies said detected channel and being recorded on a magnetic tape by said VCR to identify a source of a program signal recorded on said magnetic tape with said channel identification signal.

Claim 22

An apparatus for monitoring usage of a video monitoring system that includes a video monitoring device and a VCR, the apparatus comprising: means for supplying a channel detection signal to an input terminal of said VCR; means for detecting that said channel detection signal is present in a signal outputted from an output terminal of said VCR and for determining to which channel said VCR is tuned; and signal supply means for supplying a channel identification signal to an RF input of said VCR, said channel identification signal including data that identifies said detected channel and being recorded on a magnetic tape by said VCR to identify a source of a program signal recorded on said magnetic tape with said channel identification signal.

Claim 23

An apparatus for monitoring usage of a video monitoring system that includes a video monitoring device and a VCR, the apparatus comprising: means for supplying a channel detection signal to an input terminal of said VCR; means for detecting that said channel detection signal is present in a signal outputted from an output terminal of said VCR and for determining to which channel said VCR is tuned; and signal supply means for supplying a channel identification signal to an RF input of said VCR, said channel identification signal including data that identifies said detected channel and being recorded on a magnetic tape by said VCR to identify a source of a program signal recorded on said magnetic tape with said channel identification signal.

Claim 28

A method of monitoring usage of a video recording device that is tuned to a channel in order to receive a program signal, said video recording device being selectively operated in a recording mode in which said program signal is recorded on a recording medium, the method comprising the steps of: detecting by means of a monitoring device said channel to which said video recording device is tuned; detecting by means of said monitoring device timing pulses present in said program signal; generating by means of said monitoring device an identification signal that identifies said detected channel; modulating by means of said monitoring device an RF carrier with the generated identification signal, the RF carrier having a frequency which corresponds to the frequency of said detected channel; determining by means of said monitoring device whether said video recording device is being operated in the recording mode; and when it is determined that said video recording device is not being operated in the recording mode, repeatedly supplying said modulated RF carrier from said monitoring device to an RF input of said video recording device on the basis of said detected timing pulses and in synchronism with a first set of scanning intervals of said program signal, and when it is determined that said video recording device is being operated in the recording mode, repeatedly supplying said modulated RF carrier from said monitoring device to the RF input of said video recording device on the basis of said detected timing signals and in synchronism with a second set of scanning intervals of said program signal so that said identification signal is recorded on said recording medium in said second set of scanning intervals of said program signal to identify a source of said program signal; said second set of intervals comprising said first set and additional scanning intervals of said program signal.

Claim 29

A method of monitoring usage of a video recording device that is tuned to a channel in order to receive a program signal, said video recording device being selectively operated in a recording mode in which said program signal is recorded on a recording medium, the method comprising the steps of: detecting by means of a monitoring device said channel to which said video recording device is tuned; detecting by means of said monitoring device timing pulses present in said program signal; generating by means of said monitoring device an identification signal that identifies said detected channel; modulating by means of said monitoring device an RF carrier with the generated identification signal, the RF carrier having a frequency which corresponds to the frequency of said detected channel; determining by means of said monitoring device whether said video recording device is being operated in the recording mode; and when it is determined that said video recording device is not being operated in the recording mode, repeatedly supplying said modulated RF carrier from said monitoring device to an RF input of said video recording device on the basis of said detected timing pulses and in synchronism with a first set of scanning intervals of said program signal, and when it is determined that said video recording device is being operated in the recording mode, repeatedly supplying said modulated RF carrier from said monitoring device to the RF input of said video recording device on the basis of said detected timing signals and in synchronism with a second set of scanning intervals of said program signal so that said identification signal is recorded on said recording medium in said second set of scanning intervals of said program signal to identify a source of said program signal; said second set of intervals comprising said first set and additional scanning intervals of said program signal.

Claim 36

An apparatus for monitoring usage of a video recording device that is tuned to a channel in order to receive a program signal, said device being selectively operated in a recording mode in which said program signal is recorded on a recording medium, the apparatus comprising: means for detecting said channel to which said device is tuned, the channel detecting means being coupled to an output terminal of said device; means for detecting timing pulses present in said program signal, the timing pulse detecting means being coupled to said output terminal of said device; means for generating an identification signal that identifies said detected channel; means for modulating an RF carrier with the generated identification signal, the RF carrier having a frequency which corresponds to the frequency of said detected channel; means for determining whether said device is being operated in the recording mode, the recording mode determining means including one of erase sensor pickup means located on or near said VCR for detecting a VCR erase signal and power consumption sensing means coupled to an input power terminal of said VCR for sensing a level of power consumption by said VCR; and means for supplying said modulated RF carrier to an RF input of the device in accordance with a timing based on said detected timing pulses; said means for supplying comprising means repeatedly supplying said modulated RF carrier in synchronism with a first set of scanning intervals of said program signal when it is determined that the device is not being operated in the recording mode and repeatedly supplying said modulated RF carrier in synchronism with a second set of scanning intervals of said program signal when it is determined that the device is being operated in the recording mode so that said identification signal is recorded on said recording medium in said second set of scanning intervals of said program signal to identify a source of said program signal; said second set of intervals comprising said first set and additional scanning intervals of said program signal.

Claim 37

An apparatus for monitoring usage of a video recording device that is tuned to a channel in order to receive a program signal, said device being selectively operated in a recording mode in which said program signal is recorded on a recording medium, the apparatus comprising: means for detecting said channel to which said device is tuned, the channel detecting means being coupled to an output terminal of said device; means for detecting timing pulses present in said program signal, the timing pulse detecting means being coupled to said output terminal of said device; means for generating an identification signal that identifies said detected channel; means for modulating an RF carrier with the generated identification signal, the RF carrier having a frequency which corresponds to the frequency of said detected channel; means for determining whether said device is being operated in the recording mode, the recording mode determining means including one of erase sensor pickup means located on or near said VCR for detecting a VCR erase signal and power consumption sensing means coupled to an input power terminal of said VCR for sensing a level of power consumption by said VCR; and means for supplying said modulated RF carrier to an RF input of the device in accordance with a timing based on said detected timing pulses; said means for supplying comprising means repeatedly supplying said modulated RF carrier in synchronism with a first set of scanning intervals of said program signal when it is determined that the device is not being operated in the recording mode and repeatedly supplying said modulated RF carrier in synchronism with a second set of scanning intervals of said program signal when it is determined that the device is being operated in the recording mode so that said identification signal is recorded on said recording medium in said second set of scanning intervals of said program signal to identify a source of said program signal; said second set of intervals comprising said first set and additional scanning intervals of said program signal.

Claim 41

A method of monitoring usage of a video monitoring system that includes a video monitoring device, a cable converter and a VCR, the method comprising the steps of: detecting by means of a monitoring device which of a plurality of channels is selected for reception by said cable converter; connecting an output terminal of said cable converter to an input terminal of said VCR; and supplying a channel identification signal from said monitoring device to an input terminal of said cable converter, said channel identification signal including data that identifies said detected channel and being recorded on a magnetic tape by said VCR to identify a source of a program signal recorded on said magnetic tape with said channel identification signal.

Claim 42

A method of monitoring usage of a video monitoring system that includes a video monitoring device, a cable converter and a VCR, the method comprising the steps of: detecting by means of a monitoring device which of a plurality of channels is selected for reception by said cable converter; connecting an output terminal of said cable converter to an input terminal of said VCR; and supplying a channel identification signal from said monitoring device to an input terminal of said cable converter, said channel identification signal including data that identifies said detected channel and being recorded on a magnetic tape by said VCR to identify a source of a program signal recorded on said magnetic tape with said channel identification signal.

Claim 45

An apparatus for monitoring usage of a video monitoring system that includes a video monitoring device, a cable converter and a VCR, the apparatus comprising: channel detection means for detecting which of a plurality of channels is selected for reception by said cable converter, said channel detection means being included in said monitoring device and being coupled to at least one of an input terminal and an output terminal of said cable converter; means for connecting said output terminal of said cable converter to an input terminal of said VCR; and means for supplying a channel identification signal to an input terminal of said cable converter, said channel identification signal including data that identifies said detected channel and being recorded on a magnetic tape by said VCR to identify a source of a program signal recorded on said magnetic tape with said channel identification signal, the supplying means being included in said monitoring device.

Claim 46

An apparatus for monitoring usage of a video monitoring system that includes a video monitoring device, a cable converter and a VCR, the apparatus comprising: channel detection means for detecting which of a plurality of channels is selected for reception by said cable converter, said channel detection means being included in said monitoring device and being coupled to at least one of an input terminal and an output terminal of said cable converter; means for connecting said output terminal of said cable converter to an input terminal of said VCR; and means for supplying a channel identification signal to an input terminal of said cable converter, said channel identification signal including data that identifies said detected channel and being recorded on a magnetic tape by said VCR to identify a source of a program signal recorded on said magnetic tape with said channel identification signal, the supplying means being included in said monitoring device.

Claim 52

An apparatus for detecting a mode of operation of a VCR which has an input terminal for receiving input video signals and an RF output terminal for outputting RF modulated video signals, the VCR being selectively operated in a first mode in which said input video signals are passed through to said RF output terminal without tuning and a second mode in which a tuned RF modulated video signal is output via said RF output terminal, the apparatus comprising: means for supplying a code signal to said input terminal of the VCR; means for receiving and tuning a signal output from said RF output terminal in order to .provide a tuned video signal for display by a display device; and means for determining whether said code signal is present in said signal that was received and tuned, determining that the VCR is in said first mode if said code signal is present in said signal that was received and tunedt and determining that the VCR is in said second mode if said code signal is not present in said signal that was received and tuned.

Claim 53

An apparatus for detecting a mode of operation of a VCR which has an input terminal for receiving input video signals and an RF output terminal for outputting RF modulated video signals, the VCR being selectively operated in a first mode in which said input video signals are passed through to said RF output terminal without tuning and a second mode in which a tuned RF modulated video signal is output via said RF output terminal, the apparatus comprising: means for supplying a code signal to said input terminal of the VCR; means for receiving and tuning a signal output from said RF output terminal in order to .provide a tuned video signal for display by a display device; and means for determining whether said code signal is present in said signal that was received and tuned, determining that the VCR is in said first mode if said code signal is present in said signal that was received and tunedt and determining that the VCR is in said second mode if said code signal is not present in said signal that was received and tuned.

Claim 55

A method of monitoring usage of a VCR that is selectively operated in a playback mode in which the VCR reproduces a video signal from a videotape, the method of comprising the steps of: sequentially supplying a plurality of channel detection signals to an RF input terminal of the VCR; monitoring signals output from the VCR; and detecting that the VCR is being operated in the playback mode by determining that none of said channel detection signals are present in said signals output from the VCR.

Claim 56

A method of monitoring usage of a VCR that is selectively operated in a playback mode in which the VCR reproduces a video signal from a videotape, the method of comprising the steps of: sequentially supplying a plurality of channel detection signals to an RF input terminal of the VCR; monitoring signals output from the VCR; and detecting that the VCR is being operated in the playback mode by determining that none of said channel detection signals are present in said signals output from the VCR.

Claim 58

An apparatus for monitoring usage of a VCR that is selectively operated in a playback mode in which the VCR reproduces a video signal from a videotape, the apparatus comprising: means for sequentially supplying a plurality of channel detection signals to an RF input terminal of the VCR; means for monitoring signals output from the VCR; and means for detecting that the VCR is being operated in the playback mode by determining that none of said channel detection signals are present in said signals output from the VCR.

Claim 59

An apparatus for monitoring usage of a VCR that is selectively operated in a playback mode in which the VCR reproduces a video signal from a videotape, the apparatus comprising: means for sequentially supplying a plurality of channel detection signals to an RF input terminal of the VCR; means for monitoring signals output from the VCR; and means for detecting that the VCR is being operated in the playback mode by determining that none of said channel detection signals are present in said signals output from the VCR.

Claim 69

An apparatus for receiving channel detection and channel identification signals generated by injection signal generating circuitry and applied to and transmitted through an RF channel selection device, the apparatus comprising: an input terminal for receiving signals output from said RF channel selection device; means for selectively coupling said input terminal to one of a plurality of channel selection devices; means for transmitting a signal indicative of a level of said signals output from said RF channel selection device being below a predetermined level; means for transmitting to a control means signals indicative of timing pulses present in a video signal output from the channel selection device, said timing pulses being indicative of vertical and horizontal scanning periods of said video signal; means connected to said input terminal for generating a hit signal in response to said channel detection signal being present at said input terminal and for transmitting said hit signal to said control means; and means connected to said input terminal for transmitting data contained in said received channel identification signal to said control means.

Claim 70

An apparatus for receiving channel detection and channel identification signals generated by injection signal generating circuitry and applied to and transmitted through an RF channel selection device, the apparatus comprising: an input terminal for receiving signals output from said RF channel selection device; means for selectively coupling said input terminal to one of a plurality of channel selection devices; means for transmitting a signal indicative of a level of said signals output from said RF channel selection device being below a predetermined level; means for transmitting to a control means signals indicative of timing pulses present in a video signal output from the channel selection device, said timing pulses being indicative of vertical and horizontal scanning periods of said video signal; means connected to said input terminal for generating a hit signal in response to said channel detection signal being present at said input terminal and for transmitting said hit signal to said control means; and means connected to said input terminal for transmitting data contained in said received channel identification signal to said control means.

Claim 71

An apparatus for receiving channel detection and channel identification signals generated by injection signal generating circuitry and applied to and transmitted through an RF channel selection device, the apparatus comprising: an input terminal for receiving signals output from said RF channel selection device; means connected to said input terminal for generating a hit signal in response to said channel detection signal being present at said input terminal and for transmitting said hit signal to a control means, said hit signal generating means including means for generating a log power signal that varies as a function of the logarithm of the spectral energy, in a predetermined frequency band, of a signal present at said input terminal; means for integrating said log power signal; means for amplifying said integrated log power signal; means for averaging said amplified signal to produce a reference signal; and means for comparing said amplified signal to said reference signal and generating said hit signal in response to a level of said amplified signal exceeding a level of said reference signal by a predetermined factor; and means connected to said input terminal for transmitting data contained in said received channel identification signal to said control means.

Claim 72

An apparatus for receiving channel detection and channel identification signals generated by injection signal generating circuitry and applied to and transmitted through an RF channel selection device, the apparatus comprising: an input terminal for receiving signals output from said RF channel selection device; means connected to said input terminal for generating a hit signal in response to said channel detection signal being present at said input terminal and for transmitting said hit signal to a control means, said hit signal generating means including means for generating a log power signal that varies as a function of the logarithm of the spectral energy, in a predetermined frequency band, of a signal present at said input terminal; means for integrating said log power signal; means for amplifying said integrated log power signal; means for averaging said amplified signal to produce a reference signal; and means for comparing said amplified signal to said reference signal and generating said hit signal in response to a level of said amplified signal exceeding a level of said reference signal by a predetermined factor; and means connected to said input terminal for transmitting data contained in said received channel identification signal to said control means.

Claim 73

An apparatus for receiving channel detection and channel identification signals generated by injection signal generating circuitry and applied to and transmitted through an RF channel selection device, the apparatus comprising: an input terminal for receiving signals output from said RF channel selection device including a video signal having horizontal scanning intervals; means connected to said input terminal for generating a hit signal in response to said channel detection signal being present at said input terminal and for transmitting said hit signal to a control means; and means connected to said input terminal for transmitting data contained in said received channel identification signal to said control means and including means responsive to a control signal supplied thereto for preventing said data transmitting means from transmitting data at times other than predetermined ones of said horizontal scanning intervals of said video signal.

Claim 74

An apparatus for receiving channel detection and channel identification signals generated by injection signal generating circuitry and applied to and transmitted through an RF channel selection device, the apparatus comprising: an input terminal for receiving signals output from said RF channel selection device including a video signal having horizontal scanning intervals; means connected to said input terminal for generating a hit signal in response to said channel detection signal being present at said input terminal and for transmitting said hit signal to a control means; and means connected to said input terminal for transmitting data contained in said received channel identification signal to said control means and including means responsive to a control signal supplied thereto for preventing said data transmitting means from transmitting data at times other than predetermined ones of said horizontal scanning intervals of said video signal.

Claim 76

An apparatus for receiving channel detection and channel identification signals generated by injection signal generating circuitry and applied to and transmitted through an RF channel selection device, the apparatus comprising: an input terminal for receiving signals output from said RF channel selection device; means connected to said input terminal for generating a hit signal in response to said channel detection signal being present at said input terminal and for transmitting said hit signal to a control means, said hit signal generating means including means for generating a ramp signal in response to said channel detection signal being present at said input terminal; means for differentiating said ramp signal; means for filtering said differentiated signal; means for buffering said filtered signal; and means for comparing said buffered signal against a reference level and generating said hit signal in response to said buffered signal being not less than said reference level; and means connected to said input terminal for transmitting data contained in said received channel identification signal to said control means.

Claim 77

An apparatus for receiving channel detection and channel identification signals generated by injection signal generating circuitry and applied to and transmitted through an RF channel selection device, the apparatus comprising: an input terminal for receiving signals output from said RF channel selection device; means connected to said input terminal for generating a hit signal in response to said channel detection signal being present at said input terminal and for transmitting said hit signal to a control means, said hit signal generating means including means for generating a ramp signal in response to said channel detection signal being present at said input terminal; means for differentiating said ramp signal; means for filtering said differentiated signal; means for buffering said filtered signal; and means for comparing said buffered signal against a reference level and generating said hit signal in response to said buffered signal being not less than said reference level; and means connected to said input terminal for transmitting data contained in said received channel identification signal to said control means.

Claim 78

A method of determining whether a channel selection device is receiving an input signal from a predetermined signal source, said method comprising the steps of: receiving a video baseband signal originating from said channel selection device, said video baseband signal having vertical blanking intervals that each include a plurality of horizontal scanning intervals; separating vertical and horizontal synchronizing signals from the received video baseband signal; selecting first, second and third ones of said plurality of horizontal scanning intervals in one of said vertical blanking intervals of said received video baseband signal; interrupting said input signal during said second and third horizontal scanninq intervals and supplying a comparison signal to said channel selection device during said third horizontal scanning interval; generating a respective sample level for each of said first, second and third horizontal scanning intervals, by sampling and holding a level of said received video baseband signal during each of said first, second and third horizontal scanning intervals; storing said generated sample levels; comparing said stored sample levels; and determining that said input signal is from said predetermined signal source if said stored sample level corresponding to said third horizontal scanning interval is closer to said stored sample level corresponding to said first horizontal scanning interval than to said stored sample level corresponding to said second horizontal scanning interval.

Claim 79

A method of determining whether a channel selection device is receiving an input signal from a predetermined signal source, said method comprising the steps of: receiving a video baseband signal originating from said channel selection device, said video baseband signal having vertical blanking intervals that each include a plurality of horizontal scanning intervals; separating vertical and horizontal synchronizing signals from the received video baseband signal; selecting first, second and third ones of said plurality of horizontal scanning intervals in one of said vertical blanking intervals of said received video baseband signal; interrupting said input signal during said second and third horizontal scanninq intervals and supplying a comparison signal to said channel selection device during said third horizontal scanning interval; generating a respective sample level for each of said first, second and third horizontal scanning intervals, by sampling and holding a level of said received video baseband signal during each of said first, second and third horizontal scanning intervals; storing said generated sample levels; comparing said stored sample levels; and determining that said input signal is from said predetermined signal source if said stored sample level corresponding to said third horizontal scanning interval is closer to said stored sample level corresponding to said first horizontal scanning interval than to said stored sample level corresponding to said second horizontal scanning interval.

Claim 81

A method of determining whether a channel selection device is receiving an input signal from a cable over which a plurality of programs are transmitted simultaneously on respective channels, said cable being selectively connected to said channel selection device, said method comprising the steps of: receiving a video baseband signal originating from said channel selection device, said video baseband signal having vertical blanking intervals that each include a plurality of horizontal scanning intervals; separating vertical and horizontal synchronizing signals from the received video baseband signal; selecting first and second ones of said plurality of horizontal scanning intervals disconnecting said cable from said channel selection device during said second horizontal scanning interval; generating a respective sample level for each of said first and second horizontal scanning intervals, by sampling and holding a level of said received video baseband signal during each of said first and second horizontal scanning intervals; storing said qenerated sample levels; comparing said stored sample levels; and determining that said channel selection device is not receiving the input signal from said cable if said stored sample levels corresponding to said first and second horizontal scanning intervals differ by less than a predetermined amount.

Claim 82

A method of determining whether a channel selection device is receiving an input signal from a cable over which a plurality of programs are transmitted simultaneously on respective channels, said cable being selectively connected to said channel selection device, said method comprising the steps of: receiving a video baseband signal originating from said channel selection device, said video baseband signal having vertical blanking intervals that each include a plurality of horizontal scanning intervals; separating vertical and horizontal synchronizing signals from the received video baseband signal; selecting first and second ones of said plurality of horizontal scanning intervals disconnecting said cable from said channel selection device during said second horizontal scanning interval; generating a respective sample level for each of said first and second horizontal scanning intervals, by sampling and holding a level of said received video baseband signal during each of said first and second horizontal scanning intervals; storing said qenerated sample levels; comparing said stored sample levels; and determining that said channel selection device is not receiving the input signal from said cable if said stored sample levels corresponding to said first and second horizontal scanning intervals differ by less than a predetermined amount.

Claim 89

A method of determining whether a predetermined channel selected by a channel selection device has been changed, said channel selection device receiving an input RF video signal, said method comprising the steps of: receiving a video baseband signal originating from said channel selection device, said video baseband signal having vertical blanking intervals that include a plurality of horizontal scanning intervals; separating vertical and horizontal synchronizing signals from said received video baseband signal; selecting a first horizontal scanning interval in a vertical blanking interval of said received video baseband signal; generating a black reference level by sampling, holding and storing a level of said received video baseband signal during said first horizontal scanning interval; interrupting said input video signal during a second horizontal scanning interval in said vertical blanking interval; generating a white reference level by sampling, holding and storing a level of said received video baseband signal during said interruption of said input video signal; interrupting said input video signal during a third horizontal scanning interval in said vertical blanking interval; supplying a substitute RF video signal to said channel selection device during said interruption of said input video signal during said third horizontal scanning interval, said substitute RF video signal being at a frequency that corresponds to said predetermined channel; generating a test level by sampling, holding and storing a level of said received baseband signal while said substitute RF video signal is being supplied to said channel selection device; comparing said test level to said black and white reference levels; and determining that said predetermined channel has been changed when said test level is closer to said white reference level than to said black reference level.

Claim 90

A method of determining whether a predetermined channel selected by a channel selection device has been changed, said channel selection device receiving an input RF video signal, said method comprising the steps of: receiving a video baseband signal originating from said channel selection device, said video baseband signal having vertical blanking intervals that include a plurality of horizontal scanning intervals; separating vertical and horizontal synchronizing signals from said received video baseband signal; selecting a first horizontal scanning interval in a vertical blanking interval of said received video baseband signal; generating a black reference level by sampling, holding and storing a level of said received video baseband signal during said first horizontal scanning interval; interrupting said input video signal during a second horizontal scanning interval in said vertical blanking interval; generating a white reference level by sampling, holding and storing a level of said received video baseband signal during said interruption of said input video signal; interrupting said input video signal during a third horizontal scanning interval in said vertical blanking interval; supplying a substitute RF video signal to said channel selection device during said interruption of said input video signal during said third horizontal scanning interval, said substitute RF video signal being at a frequency that corresponds to said predetermined channel; generating a test level by sampling, holding and storing a level of said received baseband signal while said substitute RF video signal is being supplied to said channel selection device; comparing said test level to said black and white reference levels; and determining that said predetermined channel has been changed when said test level is closer to said white reference level than to said black reference level.