Victor Company of Japan, Limited

Tatsushi Koguchi

Shigehiro Ito

Yuji Nishi

Kazuyuki Ebihara

Kazuhiro Hakuno

Norihiro Usuda

Kazyuki Ebihara

An authentication/decryption unit authenticates and decrypts video signals received from a video signal output device. An open-condition detector detects the open condition of a cabinet. A memory stores therein one of a first flag indicating that an authentication operation of the authentication/decryption unit is enabled and a second flag indicating that an authentication operation of the authentication/decryption unit is disabled. A micro-controller controls whether the authentication operation of the authentication/decryption unit will be enabled or disabled according to the flag in the memory. When the open-condition detector detects that the cabinet is opened, the micro-controller writes the second flag into the memory.

Image display device

A television ghost removal apparatus comprises a transversal filter that receives input television signals, compensates waveform distortion included in the signals, and removes a ghost component; a waveform extractor that extracts signal waveforms of predetermined periods that include reference signals for ghost detection from the television signals; a coefficient setter that compares reference waveform signals and the extracted signal waveforms to obtain error signals, and sets coefficient data corresponding to the error signals, and in accordance with this coefficients data, changes filter coefficient of the transversal filter; a band limiter means for removing unnecessary high-region components included in the coefficient data, and supplying the coefficient data from which the unnecessary high-region components have been removed to the transversal filter means, the unnecessary high-region components being outside a frequency band of the reference signal; and a counter means for counting the number of times that the coefficient data have been generated by the coefficient setting means until the television signals return to a status where ghost has been removed, and for activating the band limiter means when the number of times reaches a predetermined number.

Apparatus for removing ghost from television signals including a

A ghosting cancel apparatus which can reduce the circuit scale through the use of a one-line memory to remove ghosting, comprises an A/D conversion circuit, a timing signal generation circuit, a one-line memory, a field number register, a calculation processing circuit, a transversal filter, and a D/A conversion circuit. The timing signal generation circuit supplies ghost cancel reference (GCR) field numbers to the field number register, write enable signal to the one-line memory, and read enable signals to a microprocessor inside the calculation processing apparatus. When the one-line memory receives write enable signals, and extracts GCR basic signals from the transversal filter to store them. When the microprocessor receives the read enable signals, and stores it in the waveform memory inside the calculation processing apparatus. The microprocessor performs calculation processing for compensation signals as a weighting coefficient for the transversal filter and sets and supplies it and as a result, removes ghosting from image signals.

Apparatus which employs the variable weighing coefficients for a

A waveform distortion removing apparatus includes a digital filter having taps and being controlled in response to tap coefficients. An error signal sequence is generated from a video signal. The error signal sequence contains a waveform distortion. A quadrature signal is generated which has a quadrature relation with the error signal sequence. An absolute value of the quadrature signal is derived. The absolute value of the error signal sequence and the absolute value of the quadrature signal are compared with each other. A greater of the absolute values is selected. The tap coefficients are set in dependence upon the selected greater of the absolute values.

Apparatus for removing waveform distortion from a video signal

A transversal filter filters an input video signal with a variable filtering characteristic. A waveform of a ghost cancel reference signal is periodically extracted from the input signal. An average of the successively-extracted waveforms is calculated. The filtering characteristic is determined on the basis of the calculated average of the extracted waveforms. An extracted waveform which is contaminated by an error or a jitter is rejected and is prevented from being used in the calculation of the average of the extracted waveforms.

Ghost canceler with adaptive transversal filter

Waveform distortion removing apparatus

A television ghost removal apparatus comprises a transversal filter that receives input television signals, compensates waveform distortion included in the signals, and removes a ghost component; a waveform extractor that extracts signal waveforms of predetermined periods that include reference signals for ghost detection from the television signals; a coefficient setter that compares reference waveform signals and the extracted signal waveforms to obtain error signals, and sets coefficient data corresponding to the error signals, and in accordance with this coefficients data, changes filter coefficient of the transversal filter; an S/N measurer that measures signal to a noise ratio (S/N) of the television signals; and an S/N judgment circuit that prohibits change of the filter coefficient by the coefficient setter when the S/N has deteriorated, and that initializes the coefficient data when the S/N has recovered to a favorable status. In addition, there can be provided a band limiter circuit that removes unnecessary high-region components outside a frequency band of the reference waveform signal.

Television signal according to the signal-to-noise ratio of the

A ghost cancelling device including a filtering portion made up of a transversal filter for cancelling a ghost component included in input video signals, a waveform extracting circuit for extracting a part, which corresponds to a predetermined period of time and includes a reference signal for cancelling a ghost, of a signal included in the input video signal, a waveform converting circuit for performing the waveform conversion of the signal corresponding to the predetermined of time and extracted from the input video signal, a subtracter for comparing an output of the waveform converting circuit with a preset reference waveform and outputting a signal in accordance with the result of the comparison, a coefficient setting circuit for setting coefficients having values in accordance with the output signal of the subtracter and a waveform checking circuit interposing between the waveform extracting circuit and the waveform converting circuit. The waveform checking circuit decides whether or not the output of the waveform extracting circuit should be sent to the waveform converting circuit. Thus, the ghost cancelling device can interrupt an operation of cancelling a ghost when the input video signal is abnormal and prevent occurrence of a malfunction and a runaway.

Ghost cancelling device with waveform checking circuit

A transversal filter filters an input video signal with a filtering characteristic determined by tap gains. A row of error signals are generated on the basis of a difference between a ghost cancel reference signal in the input video signal and a predetermined reference signal. A magnification setting circuit sets a first magnification in accordance with the row of the error signals. A weight setting circuit converts an output signal from the magnification setting circuit into weighting data and feeding the weighting data into the transversal filter as the tap gains. The weight setting circuit functions to correct the first magnification into a second magnification in accordance with row numbers denoting the respective error signals in the row.

Growing community of inventors

Iwai, Japan

Tatsushi Koguchi