Abstract: This invention relates to a FM receiver and more particularly to a FM receiver having an auto-scanning circuit. In a conventional FM receiver using an auto-scanning circuit, a window comparator is provided at the latter position of a demodulation circuit. When an electromagnetic wave is received, scanning is stopped by using the both of DC component of demodulation voltage generated within a specific range of frequencies around the tuning frequency and a squelch signal. In the present invention, in order to utilize stabilized parts of DC component of the demodulation voltage, as much as possible, except for the rising parts of the DC component, a timing circuit is provided which is switched on by the demodulated signal outputted from the window comparator continuing for a given time, thereby a perfect tuning is assured.

Abstract: Hand-held microphone consisting of a housing which is of such a size that said housing can be easily held by one hand, said housing including a rotary switch means which generates a digital coded signal for individually selecting one of preset frequencies and a digital coded signal for making a digital display of the channel member corresponding to the selected frequency; a channel number display means which is driven by the digital coded signal from said rotary switch means and makes a digital display of the channel number corresponding to the selected frequency; an electroacoustic transducer means; a transmit/receive switch means which switches between transmitting condition and receiving condition of a transceiver and at the same time actuates said electroacoustic transducer means; and a gain control means which varies the amplification degree of the audio amplifier and/or the radio frequency amplifier in the transceiver, whereby transmission or reception can be made by the operator who handles the transce

Abstract: A control unit for the transceiver characterized in that the whole operating portions of the transceiver is built into a housing of such a size which makes it easy to grip by one hand and the operator can remote-control the transceiver, holding the housing separate from the transceiver in his hand.

Abstract: An endodontic device for measuring and indicating the depth of penetration of a probe in a root canal of a tooth during a root canal operation includes a meter having a pair of juxtaposed, graduated scales for respectively indicating probe penetration depth in a first broad range of penetration within the root canal, and a second, relatively narrow range of penetration therein, adjacent the apex of the canal, and further includes a bidirectional indicator pointer to provide a precise, accurate visual indication of the probe penetration depth, particularly when such probe is immediately adjacent the apex of the canal. An a.c. measurement signal derived from a d.c. powered oscillator circuit is passed through the probe to a bridge circuit which measures the probe resistance, and thus the position of the probe relative to the canal apex, and also inverts the phase of the measurement signal when the probe reaches a prescribed penetration depth close to the canal apex.