Abstract: The present invention is a television receiver that includes a memory that stores a first lock release code, an input device to input a second lock release code, a comparing portion to compare the second lock release code to the first lock release code, and a control portion to output a signal to operate the television receiver when the result of the comparison conforms. Also the present invention includes a method for preventing theft of an electronic device that includes the steps of storing a lock release code in a memory of the electronic device, providing information corresponding to the lock release code to a third party, requesting an input of the information corresponding to the lock release code, comparing input information to the lock release code stored in the memory, and disabling the electronic device when the result of the comparison is not conforming.

Abstract: The present invention relates to an electronic device with an antitheft function consisting of a wireless tag containing information enabling the electronic device to operate, and a control portion accessible to the wireless tag, where the control portion releases a lock of the electronic device when the electronic device is determined to be operable according to the information stored in the wireless tag. Also, the present invention includes a method for preventing theft of an electronic device that includes the steps of writing information enabling the electronic device to operate on a memory of a wireless tag by a wireless tag writer at the time of purchase of the electronic device, and determining if the electronic device is operable according to the information written on the wireless tag.

Abstract: The present invention is a television receiver, including a counter which measures a time period for which the television receiver continuously operates, an evaluator which determines whether the time period is more than a predetermined time period and a controller which adjusts a brightness value of a picture to more than a predetermined value when the time period is more than the predetermined time period.

Abstract: An electronic device includes a memory storing a first lock release code, a comparing portion comparing the first lock release code with a second lock release code that is input with an input device, a controlling portion permitting the electronic device to operate normally if the comparing portion finds that the first lock release code matches the second lock release code, and a restricting portion restricting an acceptance of an input of the second lock release code after input attempts have been made a predetermined number of times if the comparing portion finds that the first lock release code does not match the second lock release code.

Abstract: A method of temporarily releasing viewing restriction in a television receiver employing a V chip system including the step of causing a user to enter a viewing restriction release command when the user desires to temporarily release viewing restriction based on the contents of a rating set such that a program having the rating is inhibited from being viewed, the step of making the viewing restriction based on the contents of the set rating invalid with the contents of the set rating held when the viewing restriction release command is entered, the step of causing the user to enter a viewing restriction return command when the user desires to return the viewing restriction, and the step of making the viewing restriction based on the contents of the set rating valid when the viewing restriction return command is entered.

Abstract: A PLL frquency synthesizer system television signal receiving apparatus includes a tuner, a control circuit for controlling a channel selecting operation by the tuner, and an intermediate frequency processing circuit for subjecting the IF signal outputted from the tuner to an intermediate frequency processing. The control circuit controls oscillating frequency of a local oscillating circuit in the tuner based on the PLL frequency synthesizer system. The intermediate frequency processing circuit includes an AFT signal detecting circuit for detecting a deviation of the IF signal frequency from the standard carrier frequency and feeding back the same to the control circuit. The AFT signal detecting circuit has an AFT coil which radiates higher harmonics. After a channel selection by the control circuit is completed, the AFT signal detecting circuit is rendered non-operative, so that beat interference appearing on a reproduced picture caused by the higher harmonics from the AFT coil are prevented.

Abstract: A PLL video detector comprises a phase detector circuit receiving a video intermediate frequency signal and an oscillation output of a VCO for phase-detecting the same. The phase of the oscillation output of the VCO is controlled by a signal obtained by smoothing a detection output of the phase detector circuit by a low-pass filter. In addition, a trap circuit having a center frequency of f.sub.H is provided between the phase detector circuit and the VCO, so that an unecessary component having a frequency of f.sub.H is removed from an output signal of the low-pass filter. Consequently, the VCO stably oscillates, so that occurrence of a buzz sound in a sound output and degradation of the picture quality can be prevented.