Pioneer Electronic Corporation

Toa Nenryo Kogyo Kabushiki Kaisha

Pioneer Corporation

Toa Nenryo Kogyo, K. K.

Masayuki Kato

Akio Tokumo

Takeshi Sato

Chihiro Imai

Yoshio Taguchi

Tatsuzo Hasegawa

Shinichi Suzuki

Yoshiro Kunugi

Tadashi Niwa

Tokuo Makishima, Deceased

Shuichi Mori

Toshikazu Yoshimi

Shinjiro Kato

Hisashi Kihara

Yoshio Sasaki

Fumio Tamura

Makoto Odaka

By Nobuko Makishima, Legal Representative

Akira Kanagawa

Atsushi Makino

Youichi Imai

Shinya Honjo

An in-vehicle navigation system is capable of reducing a burden on the user for utilizing an audio manipulation function. In response to a manual input manipulation, the navigation system audibly or visually presents an audio manipulation phrase which is used when the manipulation is performed through an audio manipulation.

Apparatus providing audio manipulation phrase corresponding to input manipulation

A digital graphic equalizer for obtaining a boost characteristic and an attenuation characteristic using band pass filters, each constituted by a digital filter, and an adder. For a boost characteristic, an input signal is supplied to first band pass filters and resultant filtered signals and the input signal are added by a first adder. For an attenuation characteristic, the output signal of a second adder is fed back to second band pass filters and resultant filtered signals and the input signal are added by a second adder.

Digital graphic equalizer

A power amplifier apparatus having an operational amplifier which works as a PWM (pulse width modulation) amplifier as well as an analog amplifier according to an input signal level to miniaturize the size of the apparatus and to maintain amplifying function thereof at the changeover of the function, which allows gain and frequency characteristic of the operational amplifier to have continuity before and after the changeover. The power amplifier apparatus according to the present invention comprising: an operational amplifier having two input terminals, an input signal being inputted to one of the input terminals; a triangular waveform generator for outputting voltage with triangular waveform; an input signal level detecting circuit for applying the voltage with triangular waveform from the triangular waveform generator to the other input terminal of the operational amplifier; a broadband power amplifier for amplifying an output of the operational amplifier; and a low-pass filter connected to an output terminal of the broadband power amplifier.

Power amplifier apparatus

A pulse-width modulating amplifier circuit includes two bootstrap circuits for increasing the power voltage to drive circuits to prevent a drive voltage shortage. One bootstrap circuit is connected from the output of the a power amplifier to a drive circuit. The other bootstrap circuit is connected from the output of a filter demodulator to a drive circuit.

Pulse-width modulating amplifier circuit

A balanced transformer-less pulse width modulation amplifier circuit has two filter coils wound on the same core with the same polarity relative to the output. The arrangement reduces the possibility of magnetic saturation of the core and permits the cutoff frequency to be within the audio range.

Pulse width modulation amplifier circuit

A pulse width modulation amplifier circuit pulse modulates a triangular carrier wave with an analog input, and the pulse width modulated signal is amplified and demodulated. To reduce radiated interference, the carrier is first frequency modulated by a random signal.

A pulse width modulation amplifier circuit includes a comparator which receives an analog signal and generates first and second analog signals having a phase difference of 180 degrees. A phase shifting circuit produces first and second triangular wave carrier signals so as to establish therebetween a phase difference of approximately 90 degrees. First and second pulse width modulation amplifiers, having output terminals connected to a load, pulse width modulate the first and second triangular wave carrier signals with said first and second analog signals, respectively, and amplify resultant pulse width signals.

This invention relates to a p-methyl styrene polymer represented by the following formula: ##STR1## Z denotes a group such as a functional group. Poly p-methylstyrene (PPMS) is lithiated by reaction with n-butyllithium. The lithiated PPMS is used to prepare polymers containing functional groups. As an example, a solution of PPMS (MW 260,000), 1.0 g in 20 ml of cyclohexane, was reacted with n-butyllithium, 8.5 mmol, and tetramethylethylenediamine, 8.7 mmol, for 20 hours to obtain a precipitate. The precipitate was dissolved in THF, and CO.sub.2 was blown into the solution. The solution was washed with an aqueous solution of HCl and dropped into methanol to obtain a solid polymer having carboxyl group functionality.

Process for producing a modified styrene polymer

An automatic volume control apparatus for use in a mobile audio apparatus in which a detection output from a noise detection section is compared with a control output applied to a volume control section, and a capacitor inserted between a control signal input terminal of the volume control section and a reference voltage point is charged/discharged by a current source section with a constant current on the basis of the output of the comparator to thereby make it possible to make the change of volume constant or linear relative to the change of noise level. Also, a control signal for a volume controller is obtained by subtracting a quantity of logarithmic change of an audio signal detection signal obtained from an audio signal detection section relative to a reference value from a value obtained by amplifying, with an amplification factor in a range of 1.5 to 2.5, a quantity of logarithmic change of a noise detection signal obtained from a noise detection section relative to a reference value, whereby the correspondence between levels of low-frequency components of, for example, 10 Hz or less and audible frequency components of in-vehicle noise becomes higher so that it is possible to perform more natural volume control.

Mobile automatic volume control apparatus

A polyarylene sulfide resin composition with an improved moldability and heat resistance is provided which comprises (a) 40 to 99% by weight of a polyarylene sulfide resin and (b) 1 to 60% by weight of a polyparabanic acid having the following recurring unit: ##STR1## wherein Z and Z.sup.1 are oxygen atoms or NH group, Z and Z.sup.1 being not simultaneously NH groups, and R is ##STR2## wherein R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5 and R.sup.6 are hydrogen atoms or methyl groups, and X and X.sup.1 are bonds, CH.sub.2 groups, oxygen atoms, sulfur atoms, SO.sub.2 groups, CO groups or ##STR3##

Polyarylene sulfide resin composition

An automatic sound volume device which adjusts the volume of an audio signal in a vehicle to compensate for vehicle noise. A time constant circuit smooths the level output of a microphone to smooth the volume variations. However, the time constant is long for increases in noise but short for decreases in noise.

Automatic sound volume controlling device for use in automotive vehicle

The acoustic transmission characteristics of a sound field, such as in the passenger compartment of a vehicle, are measured by placing microphones at the positions of ears of a dummy mannequin having a sound absorbing characteristic similar to that of a clothed adult human. The transmission characteristics are then corrected, such as with an automatic graphic equalizer, to provide optimized listening conditions inside the sound field for an actual listener. The use of the invention results in a listener's perception of completely natural sound.

Method and apparatus for measuring and correcting acoustic

A novel styrene copolymer having a functional group, i.e. silyl group on the para-position of the aromatic ring, useful as a functional polymer, is provided. An effective process for the production thereof comprises contacting a random or block copolymer of p-methylstyrene and .alpha.-methylstyrene with an organolithium compound to lithiate partly the p-methyl group in the copolymer and then reacting the lithiated copolymer with a silicon compound represented by the general formula (R.sup.1)(R.sup.2)(R.sup.3)SiX wherein R.sup.1, R.sup.2 and R.sup.3 are, same or different, alkyl groups with 1 to 6 carbon atoms or alkenyl groups with 2 to 6 carbon atoms, at least one of R.sup.1, R.sup.2 and R.sup.3 being an alkenyl group, and X is a halogen atom.

Novel styrene copolymer

An automatic sound field correcting system with graphic equalizer means to be provided in an audio signal supply line. A test signal such as a pink noise is radiated in the listening space and detected at a predetermined listening point to determine the detection frequency characteristic of the test signal, thereby to adjust the frequency characteristic of the graphic equalizer means. Thereafter, the frequency characteristic of the graphic equalized means is made equal to different band-pass filter characteristics, one after another, and each time the equalization is effected, the detected test signal is obtained through the grapic equalizer means for determination of the detected frequency characteristic of the test signal.

Automatic sound field correcting system

An automatic graphic equalizer for a sound system has circuitry for measuring the effect of the physical environment receiving a sound on the frequency characteristics of the sound, and for adjusting the characteristics of a graphic equalizer to compensate for distortions in the desired flat frequency response caused by the physical environment. The circuitry includes a pink noise generator supplying pink noise to the graphic equalizer during an initialization operation, the graphic equalizer being controlled by a controller to present a flat frequency characteristic. The equalizer output is sent to a speaker which supplies the pink noise as a sound signal to the selected environment. A microphone picks up the sound in the selected environment and converts it to an electrical signal which is supplied through an ALC amplifier to a frequency-variable band-pass filter to detect the signal level in each of the equalizer frequency bands. The level signals are smoothed in a level detector and digitized to be input to the controller which readjusts the graphic equalizer to compensate for distortions in the desired flat frequency response caused by the selected environment.

Growing community of inventors

Saitama, Japan

Masayuki Kato