Pioneer Corporation

Pioneer Electronic Corporation

Takao Inoue

Katsuaki Kawamura

Masashi Shimakata

Toshiaki Tsuchiya

Mitsuo Syoji

Satoshi Kaminaga

Yuichiro Shioya

Keiichi Kuroda

A digital amplifying apparatus includes a positive-phase amplifier, an inverting amplifier, a pair of LPFs, a positive and a negative noise component extracting unit, and noise component coupling units that couple a negative and a positive noise component extracted by the negative and the positive noise component extracting units with a positive and a negative PWM signals.

Digital amplifying apparatus with noise reduction

It is an object of the invention to provide an improved illumination control circuit comprising a light emission element FL, a driving elementfor driving the light emission element FL, and a compensation unitare connected in series with respect to a power source voltage Vcc. Further, a reference unitfor generating a constant voltage Vz and a detecting unitare connected in series with respect to the power source voltage Vcc. The detecting unitis provided for detecting a differential voltage Vbetween the power source voltage Vcc and the constant voltage Vz. Once there is a change in the power source voltage Vcc, the detecting unitdetects a voltage change of the power source voltage Vcc in accordance with the differential voltage V, generates a detection voltage Vformed by dividing the differential voltage V, while the compensation unitgenerates a compensation voltage Vfollowing the detection voltage V, thereby inhibiting a change of a driving voltage Vx applied between two ends of the light emission element FL and the driving element, in response to a change of the power source voltage Vcc.

Illumination control circuit

A sound volume set-point value set by the variable resistoris converted into a sound volume set-point value signal by a sound volume set-point value detecting section. A control signal generating section rectifies an input signal and adds it to a sound volume set-point value signal, thereby generating a control signal less fluctuated, and the amplification factor of amplifying section is adjusted by the control signal. The input signal is amplitude limited by this, to thereby prevent an output sound from being distorted. When the input signal is low in level, the amplitude limiting operation of the amplifier is stopped, to thereby retain a dynamic range of the original signal. Through the fluctuation suppression of the control signal, the unnatural feeling given to the listener when the amplitude limiting operation starts or stops is also lessened.

Amplifier with limiter

First resistors (R, R) for setting a forward current value are connected in series to light-emitting diodes (LED, LED) respectively to constitute first serial circuits (), which are connected to an input terminal (). Second serial circuits () are connected in parallel to the first serial circuits () respectively. The second serial circuits () are constituted by a combination of a Zener diode (ZD) and a second resistor (R), and another combination of a Zener diode (ZD) and a second resistor (R). When a higher voltage than rated voltages of the light-emitting diodes (LED, LED) is applied, the Zener diodes (ZD, ZD) shunt current into the second serial circuit () to allow the light-emitting diodes (LED, LED) to light up at desirable luminance levels different from each other. When a supplied power voltage decreases, current is not shunted, so that the same forward current flows through the light-emitting diodes (LED, LED), allowing the light-emitting diodes (LED, LED) to go off at the same timing.

Lighting device and lighting system

A rear entertainment system has a voice synthesis circuit, an OSD unit, a video camera, a DVD playback unit, a rear monitor, a navigation unit, a mixer, an IR circuit, and headphones. The voice synthesis circuit and the OSD unit receive driving information from a handle, a brake, a winker, and so on. The voice synthesis circuit presents the driving condition in an audio form, while the OSD unit presents the driving condition in a video form. The video camera takes a scene in a forward direction. The navigation unit supports the driving of the vehicle. The mixer synthesizes the voice output of the voice synthesis circuit, audio signals from the DVD playback unit and audio signals from the navigation unit. The IR circuit converts the synthesized audio signals into IR signals. The headphones receive the IR signals from the IR circuit and convert the IR signals into audio.

Rear entertainment system and control method thereof

A luminance control circuit has luminance change characteristics similar to those of a conventional lamp when a light emitting diode is used as a light source. The luminance control circuit adjusts the value of a forward current flowing in the light emitting diode in accordance with a control voltage which is obtained by smoothing a light adjustment pulse signal from an illuminance control circuit. The circuit has: a pulse adjustor for adjusting a duty factor of the light adjustment pulse signal according to characteristics of the light emitting diode; holding circuit for holding the control voltage to a predetermined value or more; and a switch for interrupting the forward current flowing in the light emitting diode by using the light adjustment pulse signal or a pulse signal after the adjustment of the duty factor, wherein at least two of these three elements are used in combination.

Light emitting diode driving circuit

A communications system for identifying a responding station called by a communications system caller station over a call channel and a plurality of speech channels. The system transmits information from the caller station, such as the selected speech channel and the designated responding station through the call channel, and receives information from a responding station on the selected speech channel. The communication between the communications system and the responding station on the selected speech channel is enabled only when information from the responding station is identical to information of the designated responding station transmitted from the communications system.

Growing community of inventors

Kawagoe, Japan

Takao Inoue