JP2006114939A - On-vehicle radio receiver - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an on-vehicle radio receiver increased in sound quality by setting radio control in response to a vehicle-mounted speaker. <P>SOLUTION: The on-vehicle radio receiver comprises: a tuner for receiving a frequency band of radio broadcast; an analog signal level adjustment unit for controlling an analog signal outputted from the tuner; a power amplifier for outputting a sound signal; a speaker for outputting sound; a current detection section for detecting a current flowing through the speaker; and a control means for detecting the type of the mounted speaker depending on the detected current and making the radio control suitable for the speaker. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an in-vehicle radio receiver capable of receiving radio broadcasts, and particularly to an in-vehicle radio receiver capable of obtaining good sound quality according to a speaker.

  Since a vehicle-mounted radio is mounted on a vehicle that is a moving body, the strength of an electric wave (electric field strength) obtained from an antenna varies depending on the influence of time zone, location, vehicle speed, and the like. Furthermore, since radio waves emitted from broadcast stations other than the reception desired station become interference waves, the interference waves may be stronger than the reception waves.

  In such a case, various contrivances have been made to suppress adverse effects such as suppression and noise as much as possible and maintain a good reception state.

  For example, automatic gain control (AGC) function, diversity antenna function, auto separation control (ASC) function, auto tone control (ATC) function, multipath auto separation control (M-ASC) function, noise canceller function, etc. in radio receiver The reception state is maintained well by providing.

  The automatic gain control (AGC) function automatically reduces the gain (gain) of the receiver when the received radio wave is strong and increases the gain of the receiver when the received radio wave is weak. This is a function that controls the amplification level to keep the output of the receiver constant.

  The diversity antenna function is a function of switching and connecting a plurality of antennas, automatically selecting an antenna having the lowest multipath noise level of the FM stereo signal, and continuously receiving FM broadcast radio waves.

  The auto separation control (ASC) function is a function that forcibly shifts to monaural reproduction when the electric field strength (RF input level) decreases, and reduces the noise level at the expense of the separation of the stereo audio signal.

  The auto tone control (ATC) function is a function that suppresses the high frequency part of the reproduced sound when the electric field strength (RF input level) is low, and reduces the noise level at the expense of sound quality.

  The multipath auto separation control (M-ASC) function forcibly shifts to monaural playback when the level of multipath noise generated by mixing the left and right channel signals of FM stereo broadcast increases, and sacrifices the separation of stereo audio signals. This is a function for reducing the level of multipath noise.

  The noise canceller function is a function that controls spike elements by detecting spike noise included in the FM demodulated signal, and shuts off the analog output of the noise portion by the gate elements. The noise canceller function removes a sudden noise component caused by the phase distortion of the FM reception signal and the ignition noise of the automobile.

  These functions send analog / digital conversion data such as RF input level from the tuner IC, which is an analog IC, to the control microcomputer circuit, execute necessary calculations in the control microcomputer circuit, and perform the necessary operations. This is achieved by sending the playback condition setting data and changing the setting contents.

  It is also possible to achieve the same function with a conventional fixed circuit having no program function. A similar function can be achieved by providing a microcomputer circuit inside an analog circuit having no communication function.

  By using the above function, it is possible to achieve high sound quality when the electric field strength is strong, and to suppress noise generation when the electric field strength is weak, thereby aiming at improvement of sound quality by performing control in accordance with the electrolytic strength.

  Furthermore, the sound quality is often improved by installing a multi-speaker system in the vehicle. Rather than combining speakers with the same characteristics, only the frequency band that the speaker itself is good at is reproduced and unnecessary sound ranges are cut. There are two-way systems that combine loudspeakers dedicated to mid- and low-pitched sounds, and 3-way systems that combine three dedicated loudspeakers dedicated to low-pitched sounds (woofer), medium-tone only (skoker), and high-temperature (tweeter) .

  Patent Document 1 also associates a radio receiver mounted on a vehicle, a position detector that detects the current position of the vehicle using a satellite system, and a reception position and frequency information of an affiliated station network. A frequency information storage unit storing the frequency map data, and a series corresponding to the current position from the position detection unit when the electric field strength of the broadcast station currently receiving in the radio reception unit is reduced below a predetermined value. A vehicle-mounted radio receiving device has been proposed that includes a control unit that reads and reads out a station from the frequency information storage unit and automatically receives it, and describes an invention that automatically changes the frequency to a current position. Yes.

JP-A-6-90140

  However, the conventional diversity antenna function, ASC function, ATC function, M-ASC function, noise canceller function, etc. effectively reduce the noise level to improve the physical quality of the reproduced sound, but the stability of the reproduced sound is impaired. However, there is a problem that the perceptual quality is reduced.

  In other words, changing the playback conditions of the tuner IC according to the electric field strength and the level of the multipath noise reduces the noise physically and makes it easier to hear even small sounds. Stereo continuity is lost and an unnatural sensation is formed.

  Therefore, if the playback conditions are made to follow the changes in electric field strength and multipath noise uniformly, the audibility fluctuates as if it vibrates, making it impossible to listen to the broadcast content comfortably. It is considered a thing.

  Therefore, the present invention intends to provide an in-vehicle radio receiver capable of detecting a speaker and performing radio control suitable for the speaker.

  A tuner for receiving a radio broadcast frequency band, an analog signal level adjuster for controlling an analog signal output from the tuner, a power amplifier for outputting an audio signal, and a speaker for outputting sound. A vehicle-mounted radio reception comprising: a vehicle-mounted radio comprising: a current detection unit that detects a current of the speaker; and a control unit that detects the speaker from the detected current and performs radio control adapted to the speaker. By providing the device, an in-vehicle radio receiver capable of performing radio control according to a speaker is provided.

  Since parameters in circuits such as AGC, ATC, and ASC, which are radio control functions, are set in accordance with the in-vehicle speakers, radio broadcasting can be enjoyed with the optimum sound quality of each speaker.

  Furthermore, in addition to the conventional control according to the electric field intensity, the radio control according to the speaker system is performed, so that higher sound quality can be provided.

  An in-vehicle radio receiver according to the present invention will be described with reference to the drawings. FIG. 1 is a block diagram of an in-vehicle radio receiver according to the present invention, and FIG. 2 is a flowchart.

  The on-vehicle radio receiver 1 includes a tuner 2 that receives a radio broadcast frequency band, an analog signal level adjuster 3 that controls an analog signal output from the tuner 2, and a power that outputs an audio signal. An amplifier 4, a speaker 5 that outputs sound, a current detector 6 that detects a current of the speaker 5, a control means 7 that detects the speaker 5 from the detected current and performs radio control adapted to the speaker 5, and an operation Input means 8 for allowing a person to input to the in-vehicle radio receiving apparatus as appropriate.

  The tuner 2 is means for demodulating a received broadcast audio signal in synchronization with a specific frequency. The tuner 2 is connected to an antenna (not shown) installed outside the automobile and the control means 7, tuned to a specific frequency in accordance with a command from the control means 7, and broadcasts received by the antenna. The audio signal is demodulated and output to the analog signal level adjuster 3.

  Note that a selector circuit may be provided before output from the tuner 2 to the analog signal level adjuster 3 to include two or more audio sources such as AM broadcast, FM broadcast, and CD player.

  The analog signal level adjuster 3 is an electronic volume circuit, and is a volume for appropriately adjusting the volume of the audio signal from the tuner 2, and outputs the audio signal to the power amplifier 4.

  The audio signal output to the power amplifier 4 is amplified and output to the speaker 5, and the speaker 5 is driven by the amplifier output to output sound.

  The current detector 6 is provided between the power amplifier 4 and the speaker 5 and measures the current value of the power amplifier output line. Since the combined resistance value differs for each speaker system mounted, the current value differs when a certain signal is reproduced. Therefore, the connected speaker is discriminated by measuring the current value. That is, the resistance value is obtained by detecting the current according to Ohm's law (current I = voltage V / resistance R), and the speaker is detected.

  After detecting the speaker, radio control parameters corresponding to the speaker are reproduced. It is desirable that parameters corresponding to the electric field strength and the mounted speaker are stored in the storage unit of the control means 7 and output from the control means 7 to the power amplifier and the tuner 2.

  A preferred embodiment of the in-vehicle radio receiver according to the present invention will be described below with reference to the block diagram of FIG. 1 and the flowchart of FIG.

  First, when a predetermined operation such as station setting or volume adjustment is performed on the operation key of the input unit 8 (A), the control unit 7 sends a signal of a predetermined frequency and level to the power amplifier 4. And output (B).

  The current value is measured by the current detector 6 (C), and the speaker 5 is determined according to the combined resistance value calculated from the detected current (D). Then, the radio control of the tuner 2 is set according to the electric field strength and the speaker 5 (E), and the process ends. In the radio control setting of the tuner 2, the parameter may be changed according to the electric field strength.

  The setting of the tuner 2 according to the speaker 5 will be described in detail. After the radio control parameters to be varied by the speaker system are stored in the control means 7 and the speaker 5 is determined, the radio control corresponding to the speaker is performed. This is done by reproducing the parameters. It is desirable that the parameter is subjected to a field test of reception performance and an appropriate numerical value is determined.

  For example, the ATC value varies from 54 dBμV to 15 dBμV with a modulation rate of 30% at 10 kHz, the ASC value is 400 Hz and the modulation rate is 30%. Below, it can be set as shown in Table 1.

  As shown in this table, it is desirable to set an adjustment value that emphasizes sound quality as the premium speaker is used.

  The tuner 2 receives the setting of the radio control based on the above parameters, tunes to a predetermined frequency, demodulates the received broadcast audio signal, and outputs it to the analog signal level adjuster 3. The analog signal level adjuster 3 appropriately adjusts the volume of the audio signal from the tuner 2 and outputs the audio signal to the power amplifier 4. Then, the audio signal output to the power amplifier 4 is amplified and output to the speaker 5, and the speaker 5 is driven by the amplifier output to perform sound output.

It is a block diagram of the vehicle-mounted radio receiver which concerns on this invention. It is a flowchart of the vehicle-mounted radio receiver which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 In-vehicle radio receiver 2 Tuner 3 Analog signal level adjuster 4 Power amplifier 5 Speaker 6 Current detection part 7 Control means 8 Input means

Claims (1)

A tuner for receiving a radio broadcast frequency band, an analog signal level adjuster for controlling an analog signal output from the tuner, a power amplifier for outputting an audio signal, and a speaker for outputting sound. A vehicle-mounted radio receiver comprising: a vehicle-mounted radio including a current detection unit that detects a current of the speaker; and a control unit that detects the speaker from the detected current and performs radio control adapted to the speaker. apparatus.

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