Abstract: A reception quality as stable as possible, by correctly judging a situation in which an operation of changing a reception condition is necessary, and preventing a reception state from getting worse even if it is already in a bad state. At the time of a normal reception, the BER of a received transmission signal is measured, and if the value of the BER has exceeded a specified value, the operation of changing the reception condition is started, and a CNR is measured. If the value of the CNR has exceeded its previous value, the reception condition will be changed, and if it has become lower than its previous value, the reception condition will be returned back to its previous condition. In this way, it is possible to obtain a stable reception quality by searching for an optimal reception condition utilizing CNR and selecting an antenna corresponding to the reception condition thus found.

Abstract: A switching circuit is provided on a high frequency line forming a switch (SW). A plurality of switching circuits are provided for each high frequency line. A plurality of switching circuits provided at the same position are set as shunt circuits (S1, S2). In addition to providing a plurality of switching circuits at the same position, by separately providing a drive circuit for each switching circuit, the reliability can be improved. With a multiple-step structure in which a plurality of switching circuits are provided at different positions on the high frequency line, isolation between input and output is improved. By using a semiconductor element such as a PIN diode as a switching element within a switching circuit, it is possible to reduce numbers of maintenance services and maintenance personnel to facilitate usage, to reduce the size and cost, and to achieve high speed.

Abstract: An S/N ratio measuring method of a video signal which is suitable for the formation of an IC and can precisely detect a fluctuation of an S/N ratio of a video signal at high response speed while suppressing the total cost and a system based on this method. In operation, a composite video signal is received, a noise density in a predetermined period of the composite video signal is detected, and an S/N ratio of a video signal included in the composite video signal is recognized basis on the detected noise density. The S/N ratio measuring system has a demodulator for demodulating the composite video signal from the reception signal and a counter for counting noises which are generated in a predetermined period of time of the composite video signal and recognizes the S/N ratio of the video signal included in the composite video signal based on a count value obtained.

Abstract: A safety circuit for a press die cushion wherein the press die cushion has a pad that is resiliently supported by a cushion cylinder which is supplied with a pilot pressure via an air delivery circuit, and wherein the press die cushion has a locking circuit for locking the pad. The safety circuit includes a first electromagnetic valve which is electrically switchable in two directions for controlling delivery of the pilot pressure to an air supply valve in the air delivery circuit to the cushion cylinder, and for controlling the air supply valve in order to lift the pad up and down. An on and off valve is disposed in a pilot pressure delivery passage of the air delivery circuit, and is opened when the pad lies in a vicinity of a lower limit position. A second electromagnetic valve is connected to the on and off valve.

Abstract: A high frequency signal is inputted to a receiver from an antenna for receiving the high frequency signal.

Abstract: An NF (Negative Feedback) tone control circuit in which a circuit gain of unity is maintained for a flat frequency response without the addition of active components. A voltage divider circuit which divides only an a.c. component of the output of an operational circuit is connected between the output of the operational amplifier circuit and a variable impedance circuit, the latter including the variable resistors of the tone control circuit.

Abstract: A device for generating a tuning frequency set command signal for a tuner system having a manual tuning mode and an automatic channel scanning mode, including a manually operable means for generating an up control signal for raising the tuning frequency and a manually operable means for generating a down control signal for lowering the tuning frequency, and timing means for measuring the duration of the up or down control signal, and control means for automatically selecting the automatic channel scanning mode when the duration of the up or down control signal becomes longer than a predetermined time period, is characterized by a reset means for resetting the timing means each time when the up or down control signal disappears, thereby alleviating the fear that the automatic channel scanning mode is erroneously selected when the means for generating up or down control signal is operated more than one time within the predetermined time period.