Pioneer Electronic Corporation

Reisuke Sato

Tomohisa Yokogawa

Tadashi Ogawa

Yoshiharu Ueki

Hisashi Suganuma

Tadashi Kosuga

Masanao Okatani

Yoshiaki Ishibashi

Haruo Kama

Hiroshi Onishi

Shizuo Ando

Yoshiro Sugai

A level shifting circuit capable of operating with a wide range of impedances of a signal source without backflow of current and without a buffer circuit. A feedback element is coupled between an inverting input and an output of an operational amplifier. An output of a current source is connected to the inverting input of the operational amplifier while the signal to be level shifted is applied to the non-inverting input thereof. The current source may be a current mirror circuit and a temperature compensating diode may be coupled in series with the feedback element.

Level shifting circuit

A tape recorder/reproducer of the automatic reverse type includes fast forward and reverse buttons which are switchably connected to the fast tape speed direction controls so that the desired operation corresponding to the actuated button is carried out irrespective of whether the tape is currently being played in the normal or reverse direction.

Drive mode switching device for magnetic tape recorder/reproducer

An FM receiver including a noise suppressing circuit in which the signal from which the noise is detected is taken from a front-end section of the receiver and a correction to the noise is made prior to the detector of the receiver. The noise is suppressed by terminating the received signal upon detection of the presence of noise and holding the level which was present before the noise was detected for a predetermined period of time. By detecting the noise in a signal from the front end of the receiver and by making the correction prior to the detector circuit, only a very short predetermined time period need be used and no complicated pilot signal processing circuit is required.

Noise suppressing device in FM receiver

A car-mounted audio equipment of multiamplifier system including a single preamplifier, a plurality of power amplifiers and the corresponding number of differential amplifiers each connected between an output terminal of the preamplifier and an input terminal of each of the power amplifiers comprises a biasing means for biasing at least one of the ground terminals of the power amplifiers to a potential substantially equal to the ground potential when the one terminal is in an open state.

Car-mounted audio equipment

An electronic tuning type receiver comprises a digital-to-analog conversion section having a memory adapted to store a digital input value obtained by counting pulses generated by a manual operation. In one embodiment an up-down counter is also employed. A digital-to-analog conversion process section generates a pulse signal having a number of pulses per unit time corresponding to an output of the memory or counter and a tuning section receives as a tuning signal, an analog output signal of the digital-to-analog conversion section. The receiver further comprises an electric source 'off' state detecting circuit which, in one embodiment only when both of the outputs of the digital-to-analog conversion process section and an electric source thereof are brought to be in 'off' state, operates to suspend the operations of relevant sections of the receiver. In another embodiment the up-down counter and pulse oscillator are suspended when the power is switched off.

Electronic tuning type receiver with digital to analog converter

A manual tuning pulse generator for use in an electronic tuning control device of a radio receiver having a tuning circuit, which control device utilizes an up/down counter, is disclosed which comprises a first manual means for selectively producing an up count signal and a down count signal to be supplied to the up/down counter, a second manual means ganged with said first manual means for producing a variable control signal and means responsive to the variable control signal to produce a clock pulse signal having a variable frequency, the pulses of the clock pulse signal being adapted to be counted up or down by the up/down counter the content of which is utilized to shift the tuning frequency.

Manual tuning pulse generator

The present invention is a magnetic tape running state and tape run amount display device which displays visually the running direction and speed or the run amount and direction of the magnetic tape. An up-down counter is provided with a clock input signal having a pulse generated in correspondence with the run of the tape and is also provided with a count control signal. The count control signal has an UP signal generated when the tape is being transported in a first or forward direction, and has a DOWN signal generated when the tape is being transported in a second or reverse direction. The up-down counter provides a binary output count signal to a display circuit in correspondence with the clock input signal and the count control signal. The up-down counter can also be provided with a reset input responsive to a reset signal which acts to reset the count back to logic 0. The display circuit provides a visual representation of the binary output signal, and may include a first binary-to-digital decoder and a second binary-to-digital decoder, each being responsive to a preselected portion of the binary bits provided by the up-down counter. A plurality of light emitting diodes are connected between decimal output lines of the first and second binary-to-digital decoders for providing a visual indication of the tape running state and run amount. In one arrangement, the diodes are arranged to define a line. The display circuit also can be responsive to the binary tuning signal provided by an electronic tuning type receiver.

Magnetic tape running state and tape run amount display device

The present invention is a light receiving circuit which includes an active device and light responsive switching device. The active device has an emitter, a base and a collector, the base being responsive to a first constant voltage source and the collector being responsive to a second voltage source. The light responsive switching device has a first lead and a second lead, the first lead being connected electrical ground and the second lead being connected to the emitter of the active device. The light receiving circuit of the present invention exhibits a high response speed and a stable output waveform. In another embodiment, the light receiving circuit of the present invention includes two active devices and two light responsive switching devices.

Light receiving circuit having fast response time and a stable output

Power is provided for maintaining the contents of the memory in a digital receiver by providing a second output terminal for driving the memory element when either the power switch is turned off or the main power supply is interrupted.

Power supply circuit for an electronic tuning type receiver with a

The present invention is an electronic tuning type receiver having a band display unit and a numerical frequency display unit. The numerical frequency display unit provides a visual numerical display of the frequency selected by the receiver. The band display unit provides a visual indication of the relationship of the selected frequency with respect to the frequency band being tuned by the receiver.

Electronic tuning type receiver having a band display and numerical

A combination device having a magnetic recording and reproducing unit and an electronic tuning type receiver, where the channel presetting switches of the electronic tuning type receiver also can act as the operating switches of the magnetic recording and reproducing unit. The electronic tuning type receiver is of the type which is tuned by control signals provided to a tuning means by a plurality of channel selecting switches. A selection circuit is interposed between the tuning means and the plurality of channel selecting switches and provides the plurality of control signals to the tuning means when a selection switch is in a first binary state, and provides the plurality of control signals to a tape-control section when the selection switch is in a second binary state. The tape-control section, in response to the plurality of control signals, controls the mode of operation of the magnetic recording and reproducing unit, and also provides a signal indicating the mode of operation to a sensing circuit. The sensing circuit, in turn, provides mode signals to a digital display unit which can visually display the mode of operation when the magnetic recording and reproducing unit is being used, as well as can visually display the station frequency or the like of the selected station when the electronic tuning type receiver is being used.

Combination device having a magnetic recording and reproducing unit and

During preset station selection operation in a digital receiver the station selection switch most recently operated is indicated by a light so as to prevent erroneous operation at the same switch again.

Station selection indicating device

Muting is provided for a receiver during preset channel selection by using the output signals from each channel selection switch to energize a muting circuit. During manual channel selection or during the resetting operation no muting is provided.

Muting circuit in an electronic tuning type receiver

A preset state indicating unit for use in an electronic tuning type receiver generates a visual indication when both a presetting switch and one of a plurality of channel selecting switches have been properly selected. The preset state indicating unit thus insures that tuning information pertaining to a selected station is actually stored in memory during the presetting operation done by the user.

Growing community of inventors

Kawagoe, Japan

Reisuke Sato