JPH0559611B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an improvement in an in-vehicle radio receiver that searches for stations with the same broadcast content while the vehicle is driving.

[Conventional technology]

FIG. 7 is a diagram showing the configuration of a conventional in-vehicle radio receiver that identifies the same broadcast as disclosed in Japanese Patent Application Laid-Open No. 57-207415. In FIG. This is a tuner connected to antenna 1.

The received level of the received signal tuned by the tuner 2 is detected by the level determination circuit 3 and sent to the control section 5.

Further, a demodulation output detection circuit 4 is configured to detect an interruption in the sound of the demodulation output of the tuner 2. This detection output is also sent to the control section 5.

The data memory 6 is controlled by the output from the control section 5. The data memory 6 includes a current station data area 6a and an inspection station data area 6.
It is composed of b.

The term "current station" here means the station currently receiving data, and the term "testing station" refers to a station other than the station currently receiving data.

A tuning voltage corresponding to the data stored in the data memory 6 is generated by a tuning voltage generation circuit 7 and applied to the tuner 2, and the tuner 2 uses this tuning voltage to tune the received signal. ing.

Further, the muting circuit 8 is controlled by the control section 5, and furthermore, the signal demodulated by the tuner 2 is transmitted to the low frequency amplification circuit 9.
The amplified signal is used to drive the speaker 10.

Next, the operation will be explained. The data of the station currently being received is in the current station data area 6 of the data memory 6.
This data is applied to the tuning voltage generating circuit 7, and the tuner 2 is tuned based on the output of the tuning voltage generating circuit 7 to receive the broadcast program of the current station.

The level of the received signal of the current station received by the tuner 2 is given to a determination circuit 3, and the demodulated output is given to a demodulated output detection circuit 4, and the output of the level determination circuit 3 is accumulated and averaged by a control section 5. , is stored in the current station data area 6a as the reception level of the current station.

Next, when the output of the demodulation output detection circuit 4 detects a sag in the sound for a certain period of time, the control section 5 first applies muting to the muting circuit 8 to attenuate the sound output level and interrupt the sound in order to prevent noise generation.

Next, the current station data area 6 of the data memory 6
The frequency data stored in the inspection station data area 6b and the inspection station data area 6b are exchanged, and the frequency data stored in the original inspection station data area 6b is given to the tuner 2 through the tuning voltage generation circuit 7, tunes to that frequency and receives the corresponding station. As in the case of the current station, the received signal of the tuner 2 is applied to the control section 5 through the level determination circuit 3.

If the reception level of the current station is higher, the control unit 5 immediately cancels muting and switches to the current station data area 6a of the data memory 6, and the frequency data of the inspection station data area 6b is transferred to the next receivable station. data, and returns to reception of the current station.

Again, each time a sound break is detected by the demodulation output detection circuit 4, muting is applied in the same manner as described above, the reception levels of the test station and the current station are compared, and the entire reception band is searched.

When the receiving level of the testing station becomes higher than the receiving level of the current station, the control unit 5 takes in the output of the demodulation output testing circuit 4, and if sound breakage is detected at the same time as the current station, the control unit 5 reads the data in the testing station data area 6b. Cancel muting without making any changes and return to the current station.

At the moment of the next sound break, the system switches to the inspection station data area 6b and performs the sound break test again. After repeating this test several times, the control unit 5 enters a state of waiting for the output of the current station to rise, and at the moment the output of the demodulated output detection circuit 4 of the current station rises, it switches to the testing station and outputs the demodulated output. It detects the output of the detection circuit 4, immediately cancels muting, and returns to the current station.

At this time, if the outputs rise at the same time,
If the inspection is continued and there is a sound break at the end after detecting the rise several times, it is determined that the broadcast content is the same, and the control unit 5 updates the inspection station data area 6 of the data memory 6.
Muting is canceled while the stored data of b and the current station data area 6a are exchanged. Therefore, it automatically switches to the one with the higher reception level for the same broadcast content.

[Problem that the invention seeks to solve]

Conventional in-vehicle radio receivers with a content discrimination function are configured and operate as described above, so that pulse noise, such as engine ignition noise or car relay contact noise, is generated during periods of sound interruption. If the reception level of the broadcast is high compared to the reception level of the broadcast, interruptions in the broadcast wave cannot be detected, and switching from the current station to the inspection station cannot be performed normally even if the broadcast content is the same.

In addition, there were problems in that the inspection time was long and it took time to switch.

This invention was made in order to solve these problems, and is an in-vehicle device that can prevent malfunctions caused by pulse noise such as ignition noise and car relay contact noise, and can correctly determine the content. The purpose is to obtain a radio receiver.

[Means for solving problems]

The in-vehicle radio receiver according to the present invention includes a noise detection circuit that detects noise in the output of the tuner;
A control section is provided which inputs the output of this noise detection circuit and switches between the current station and the inspection station.

Further, an in-vehicle radio receiver according to another aspect of the present invention is provided with a switching circuit that switches the inductance or resistance of the ignition coil based on the output from the noise detection circuit.

[Effect]

In this invention, only during the period when pulse noise is detected by the noise detection circuit from the output of the tuner, the control section stops or switches the operation of comparing the reception strength and modulation content of the current station and the inspection station, and increases or decreases the number of times. conduct.

Further, in another invention of the present invention, the value of the inductance or resistance of the ignition coil of the engine is switched by the switching circuit only during the period detected by the noise detection circuit, the ignition energy is reduced, and the generation of pulse noise is prevented. suppress.

〔Example〕

Embodiments of the in-vehicle radio receiver of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the configuration of one embodiment. In FIG. 1, parts that are the same as those in FIG. 7 are given the same reference numerals, and their explanation will be omitted, and the parts that are different from FIG. 7 will be mainly described.

As is clear from a comparison between FIG. 1 and FIG. 7, the parts indicated by numerals 1 to 10 in FIG. 1 are exactly the same as those in FIG. A noise detection circuit 11 is newly added to the above.

This noise detection circuit 11 detects pulse noise from the intermediate frequency amplification stage of the tuner 2, and its output controls switching between the current station and the inspection station in the control section 5.

Further, 12 is an indicator indicating that switching between the current station and the inspection station has been stopped due to noise. The display operation of the six display devices 12 is controlled by the control section 5.

FIG. 2 is a block diagram showing the configuration of a commonly used noise detection circuit 11. In this FIG. This is a high-pass filter (hereinafter referred to as HPF) for extraction.

The signal output from this HPF22 is sent to the amplifier 2
3, and a noise detector 24 detects only the noise signal from the amplified high-frequency component signal.

A monostable altivibrator 25 is activated by the noise pulse signal detected by the noise detector 24. The output of this monostable multivibrator 25 is taken out from an output terminal 26 and applied to the control section 5 shown in FIG.

The control section 5 is configured as shown in FIG. As is clear from FIG. 3, the output of the noise detection circuit 11 passes through the inversion circuit 17 and is applied to the first input terminal of the AND circuit 16. , the output of the demodulation output detection circuit 4 is input.

Output of AND circuit 16 and level judgment circuit 3
The output of the switching signal generating circuit 18 is inputted to the switching signal generating circuit 18, and the output of this switching signal generating circuit 18 is outputted to the display 12 via the stop display control circuit 19, and is also input to the data memory 6. It is now output.

Next, the operation of this embodiment will be explained. First, pulsed noise is received by the antenna 1, passes through the intermediate frequency amplification stage of the tuner 2, and the output of the noise detection circuit 11 connected thereto has the waveform shown in Figure 4a, and pulsed noise is detected. The inversion circuit 17 outputs a high level only while the
The waveform shown in FIG. 4b is output.

Next, in the demodulation output detection circuit 4, when a sound break is detected in the modulation output, the waveform shown in FIG. 4c is outputted. AND circuit 1 of these two outputs
6, this output is output during the output period of the demodulation output detection circuit 4 (T1 to T1 in FIG. 4).
During the period T4), the output of the noise detection circuit 11 is at a high level.

During periods T1 and T4 in FIG. 4, the high level signal shown in FIG. 4d is not output from the AND circuit 16, and a high level signal is output only during periods T2 and T3.

This output is the switching signal generating circuit 18 in the control section 5.
When the frequency data is input to the current station, a switching signal is generated only during the periods T2 and T3 in FIG. Performs an operation to search for inspection stations for broadcast content.

Further, when the switching between the current station and the inspection station is stopped due to the incidence of pulse noise, the display 12 is turned on by the stop display control circuit 19 during that time.

In the above embodiment, the noise detection circuit 11 is connected to the intermediate frequency amplification stage or the noise removal circuit of the tuner 2 to extract pulsed noise from the received signal as a means for detecting pulsed noise. A pulse detection circuit 13 and an ignition signal connection terminal 14 are provided as shown in FIG.
For example, since pulse noise is thought to occur depending on the engine speed, the output of a tachometer or the like may be directly connected.

In this case, the content determination is stopped at the moment the engine is ignited, and the same effect as in the above case can be obtained.
Furthermore, the number of times the current station and inspection station are switched can be increased or decreased depending on the engine speed.

Now, in the above invention, the output from the noise detection circuit 11 controls switching between the current station and the inspection station in the control section 5, but the system shown in FIG. 6 was devised in order to suppress the pulse noise generation source. be. During the period when pulse noise is detected by the noise detection circuit 11, the ignition switching circuit 15 switches the inductance or resistance value of the ignition coil to a constant with low ignition energy to the extent that running is not affected, thereby generating pulse noise. It is possible to suppress the noise level to a level that does not affect the detection of sound interruptions in the demodulation output detection circuit 4, and it is possible to perform a good content discrimination operation.

Also in FIG. 6, the display device may be operated by the output of the control section 5 as in FIG. 1.

〔Effect of the invention〕

As explained above, this invention detects pulse noise and controls switching between the current station and the inspection station while pulse noise is being detected. By not losing the middle switching timing, it is possible to select broadcast waves with the same broadcast content without error, and there is an effect that it is possible to always worry about strong radio waves.

Another invention of the present invention is that the value of the inductance or resistance of the engine's ignition coil is switched only during the period detected by the noise detection circuit, so the ignition energy can be reduced and the pulse noise can be reduced. It has the effect of suppressing the occurrence of

[Brief explanation of the drawing]

Fig. 1 is an overall block diagram showing an embodiment of the in-vehicle audio device of the present invention, Fig. 2 is a block diagram showing a noise detection circuit in the in-vehicle radio receiver of the same, and Fig. 3 is the in-vehicle radio receiver of the same. A block diagram showing the configuration of the control unit and its peripheral parts in the machine; Figure 4 is an explanatory diagram of the operation of each part in Figure 3;
6 and 6 are block diagrams showing other embodiments of the in-vehicle radio receiver of the present invention, respectively, and FIG. 7 is a block diagram showing the configuration of a conventional in-vehicle radio receiver. DESCRIPTION OF SYMBOLS 1...Antenna, 2...Tuner, 3...Level judgment circuit, 4...Demodulation output detection circuit, 5...Control unit, 6...Data memory, 7...Tuning voltage generation circuit, 8...Mumuting circuit , 10
... Speaker, 11 ... Noise detection circuit, 12 ...
...Indicator, 13...Pulse detection circuit, 14...Ignition signal connection terminal. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Claims] 1. A tuner, a level determining means for determining a reception level by the tuner, a demodulating output means for detecting a demodulated output level of the received signal, and a tuning corresponding to a tuning key for switching the tuning frequency of the tuner. The data memory capable of storing data, the noise detection means for detecting pulse noise, and the output of the level determination means are stored in the data memory, and the demodulation output inspection means detects that the audio from the tuner lags for a predetermined period. When detected, the muting means is operated to interrupt the output of the tuner, and the tuned frequency of the tuner is switched so that the reception level is higher than the reception level of the broadcasting station currently being received, and the audio is the same as the broadcasting station currently being received. Similarly, search for the same broadcasting content station that has stopped, and if the same broadcasting content station is found, the tuning data corresponding to the broadcasting station currently being received stored in the data memory is transferred to the same broadcasting content station. In addition to rewriting the corresponding tuning data,
An in-vehicle radio receiver comprising a control unit that stops rewriting tuning data in a data memory when pulse noise is detected by noise detection means. 2. Claim 1, wherein the noise detection means inputs an intermediate frequency signal of the received signal.
In-vehicle radio receiver as described in section. 3. Claim 1, characterized in that the noise detection means takes in an engine ignition signal from the vehicle.
In-vehicle radio receiver as described in section. 4 When the output of the noise detection means is input, the control unit stops rewriting the tuning data corresponding to the broadcast station currently being received stored in the data memory to the tuning data corresponding to the same broadcast content station. An in-vehicle radio receiver according to claim 1, characterized in that the period is displayed on a period indicator. 5 a tuner, a level determining means for determining a received level by this tuner, a demodulating output detecting means for detecting a demodulated output level of the received signal, and a tuner capable of storing tuning data corresponding to a tuning key for switching the tuning frequency of the tuner. The outputs of the data memory, the noise detection means for detecting pulse noise, and the level determination means are stored in the data memory, and when the demodulation output inspection means detects that the audio from the tuner lags for a predetermined period, the muting means is activated. The output of the tuner is interrupted by operating the tuner, and the tuned frequency of the tuner is switched so that the reception level is higher than the reception level of the broadcasting station currently being received, and the audio is stopped in the same way as the broadcasting station currently being received. When searching for the same broadcast content station, if the same broadcast content station is found, the tuning data corresponding to the currently received broadcast station stored in the data memory is transferred to the tuning data corresponding to the same broadcast content station. and ignition switching means for switching the inductance or resistance value of the ignition coil to a low constant of ignition energy to such an extent that the noise detection means does not interfere with driving during the pulsed noise detection period. . 6. Claim 5, characterized in that the noise detection means inputs an intermediate frequency signal of the received signal.
In-vehicle radio receiver as described in section. 7. Claim 5, characterized in that the noise detection means takes in an engine ignition signal from the vehicle.
In-vehicle radio receiver as described in section. 8. When the output of the noise detection means is input, the control section stops rewriting the tuning data corresponding to the broadcasting station currently being received stored in the data memory to the tuning data corresponding to the same broadcast content station. The in-vehicle radio receiver according to claim 5, characterized in that the period is displayed on a period indicator.