JPH10294674A - On-vehicle audio system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable automatic switching to another signal source when the receiving state of broadcasting gets adverse in a car audio system. SOLUTION: When receiving broadcasting, a switch circuit 16 is connected to the side of the reception circuit 10, and the audio signal of broadcasting is supplied to speakers 18L and 18R. When a detecting signal S19 of the detection circuit 19 shows that the reception level of broadcasting is lowered rather than a prescribed level, the count of timer is started from an initial value. While the detecting signal S19 shows that the reception level of broadcasting is lower than the prescribed value, the count of timer is continued. When the count of timer becomes a prescribed value, the switch circuit 16 is changed over to the side of the signal source, and the other audio signal from the signal source is supplied to the speakers 18L and 18R.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a car audio system.

[0002]

2. Description of the Related Art An audio device mounted on an automobile, that is, a so-called car audio device, is generally based on a radio receiver and combined with audio equipment such as a tape player and a CD player. While driving, you can listen to broadcasts and CDs.

[0003]

However, if a car is traveling on a tunnel or mountain road while receiving a broadcast, the reception condition of radio waves may deteriorate, and the broadcast may not be received. Then, when the state in which the broadcast cannot be received continues for a long time, manual switching to CD reproduction or the like is performed.

[0004] The present invention seeks to automate such switching.

[0005]

According to the present invention, a receiving circuit for receiving a broadcast and outputting an audio signal of the broadcast, a signal source of another audio signal, an audio signal of the broadcast, A switch circuit for selecting the another audio signal and supplying the selected audio signal to a speaker;
A detection circuit for detecting the reception level of the broadcast, and a timer, and for receiving the broadcast, the switch circuit is connected to the reception circuit side and an audio signal of the broadcast is supplied to the speaker; When the detection signal of the detection circuit indicates that the reception level of the broadcast has fallen below a predetermined value, the timer starts counting from an initial value, and the detection signal of the detection circuit indicates that the reception level of the broadcast is The period indicating that it is lower than the predetermined value,
The timer continues counting, and when the timer count reaches the predetermined value, the switch circuit is switched to the signal source side to supply the another audio signal from the signal source to the speaker. This is an audio device for use in a vehicle. Therefore, if the state of poor broadcast reception continues for a predetermined period, the CD
Automatically switch to the playback state.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG.
This is the case of a car audio device in which a D player is combined, and reference numeral 10 indicates its FM receiving circuit.

In this FM receiving circuit 10,
The FM signal received by the antenna 11 is supplied to a PLL synthesizer type tuner circuit 12 to select a broadcast station of a target frequency, and the FM signal is converted into an intermediate frequency signal. The intermediate frequency signal is supplied to an FM demodulation circuit 14 through an intermediate frequency circuit 13 having an intermediate frequency filter and an amplifier. The demodulation circuit 14 demodulates and extracts a stereo composite signal.

[0008] This signal is sent to the stereo demodulation circuit 15.
To output left and right channel audio signals. These signals are connected to a switch circuit 16 and an amplifier 17 connected to the state shown in FIG.
Speakers 18L, 18R through L, 17R signal lines
R and converted to left and right channel sound.

Further, a part of the intermediate frequency signal is supplied from the intermediate frequency circuit 13 to the detection circuit 19, and a part of the demodulation output is supplied from the demodulation circuit 14 to the detection circuit 19.
From the detection circuit 19, a signal indicating the reception level of the FM broadcast, that is, “H” level when the FM broadcast can be received at a practical reception level, and “H” level when the FM broadcast cannot be received at a practical reception level The detection signal S19 at L level is taken out.

A CD player 20 is provided to extract left and right channel audio signals at the time of reproduction, and these signals are connected to a switch circuit 16 and an amplifier 17L, which are connected in a state opposite to that shown in FIG. 1
The signal is supplied to the speakers 18L and 18R through the 7R signal line, and is converted into left and right channel sounds.

Further, a microcomputer 30 is provided for controlling the system. The microcomputer 30 is provided with, for example, a routine 100 shown in FIG. 2 as a part of a program executed by the CPU (not shown). This routine 100 is executed at the time of receiving an FM broadcast, and details thereof will be described later. However, in FIG. 2, for simplicity, only portions related to the present invention are extracted and shown.

Further, various operation keys 41 are connected to the microcomputer 30 and, for example, an LCD 42 is connected as a display element. At the time of channel selection, data specifying the reception frequency is supplied from the microcomputer 30 to the tuner circuit 12, and the detection signal S19 of the detection circuit 19 is taken into the microcomputer 30.

Further, the microcomputer 30 sends C
Various control signals are supplied to the D player 20 to control the operation state of the CD player 20, and the CD player 20 sends predetermined data such as the track number of the track being reproduced and the elapsed time to the microcomputer 10. The indicated data is supplied. Further, a control signal is supplied from the microcomputer 30 to the switch circuit 16, and the switch circuit 16 is connected to the state shown in the drawing when receiving FM broadcasting, and is connected in the opposite state to the state shown in FIG.

In such a configuration, when one of the keys 41 for instructing the reproduction of a CD is operated, the microcomputer 30 connects the switch circuit 16 in a state opposite to that shown in FIG. The playback of the CD is executed under the control of the playback state,
The speakers 18L and 18R allow the user to listen to the reproduced sound of the CD.

Further, at this time, data such as the track number and elapsed time of the track being reproduced is supplied from the player 20 to the microcomputer 30, and the track number and elapsed time are displayed on the LCD 42.

When one of the keys 41 for instructing the reception of the FM broadcast is operated, the microcomputer 3
By 0, the switch circuit 16 is connected to the state shown in the figure, and therefore, the received broadcast can be heard by the speakers 18L and 18R. When a key operation for selecting a channel is performed, data of a corresponding frequency is formed by the microcomputer 30 and set in the tuner circuit 12, and the tuner circuit 12 is set to a reception state of the frequency.

Further, during reception of the FM broadcast, the microcomputer 30 executes
U executes the following processing. That is, when the key operation for instructing the reception of the FM broadcast is performed, the FM broadcast can be received and listened as described above.
The processing of the PU starts from step 101 of the routine 100, and then in step 102, a timer by software is set to an initial value, that is, a time limit determined in advance by the user.

Thereafter, the process proceeds to step 103. In this step 103, the level of the signal S19 is checked to determine whether or not the FM broadcast can be received at a practical level. = "H"), the process returns from step 103 to step 102.

Therefore, during the reception of the FM broadcast, the reception level is checked.
3 is repeated.

However, when the reception state of the radio wave deteriorates as the vehicle travels and the reception level decreases, S19 = "L"
And this is determined in step 103, and the process proceeds from step 103 to step 111.
Then, in step 111, step 102
Is counted down by the unit time, and it is checked in step 112 whether the timer has become 0. If the timer has not become 0, the process returns to step 103.

Therefore, when the reception level of the FM broadcast becomes low, the timer starts counting down, and the down-counting is continued during the period when the reception level is low. However, if the reception level becomes high during the down-counting, this is detected in step 103, the processing returns to step 102, and the processing is executed again from the beginning.

When the reception level is kept low and the period reaches the time limit set in step 102, the timer is set to 0 and this is set in step 112.
The processing proceeds from step 112 to step 121. Then, in this step 121,
The switch circuit 16 is connected in a state opposite to that shown in the figure, and a control signal for instructing the CD player 20 to enter the reproduction mode is supplied, so that the CD player 20 is set to the reproduction mode. Therefore, the reproduction sound of the CD is heard from the speakers 18L and 18R from this point.

Subsequently, the process proceeds to step 122. In this step 122, the level of the signal S19 is checked to determine whether or not the FM broadcast can be received at a practical level. Is repeated. Thus, step 12
When the reproduction of the CD is started by 1, the reception level of the FM broadcast is monitored thereafter.

When the reception level of the FM broadcast increases, this is detected in step 122, and the process proceeds from step 122 to step 131. In step 131, the switch circuit 16 is connected to the state shown in FIG. Returns to step 102. Therefore, the reproduction sound of the original FM broadcast is output from the speaker 1 from this point.
You can hear from 8L and 18R.

Thus, according to the car audio apparatus, when the reception state of the radio wave is deteriorated during the reception of the FM broadcast and the traveling of the car or the like and the broadcast cannot be received continues, the reproduction is automatically switched to the reproduction of the CD. Therefore, it becomes very convenient to use as a car audio device, and music and the like can be enjoyed more comfortably. When the FM broadcast can be received again, the original F
Since the state returns to the reception state of the M broadcast, the usability is also good from this point.

In the above description, the CD player 20 is incorporated as a signal source in the car audio device. However, the signal source may be a tape player, an MD player, or the like.

[0027]

According to the present invention, when a broadcast is received, if the reception state of the broadcast continues to be poor, the mode is automatically switched to reproduction of another signal source, so that music and the like can be enjoyed more comfortably. it can.

[Brief description of the drawings]

FIG. 1 is a system diagram illustrating one embodiment of the present invention.

FIG. 2 is a flowchart illustrating one embodiment of the present invention.

[Explanation of symbols]

10: FM receiving circuit, 12: Tuner circuit, 13: Intermediate frequency circuit, 14: FM demodulation circuit, 15: Stereo demodulation circuit, 18L and 18R: Speaker, 19: Detection circuit,
20: CD player, 30: microcomputer, 4
1 ... operation keys, 42 ... LCD, 100 ... routine

Claims (2)

[Claims] A receiving circuit for receiving a broadcast and outputting an audio signal of the broadcast; a signal source of another audio signal; selecting the audio signal of the broadcast and the other audio signal; A switch circuit for supplying the broadcast signal; a detection circuit for detecting a reception level of the broadcast; and a timer. The broadcast circuit receives the broadcast by connecting the switch circuit to the reception circuit side. To the speaker, and when the detection signal of the detection circuit indicates that the reception level of the broadcast has dropped below a predetermined value, the timer starts counting from an initial value, and the detection signal of the detection circuit While the timer indicates that the reception level of the broadcast is lower than the predetermined value, the count of the timer is continued, When it becomes the value, the audio device for vehicle in which the said another audio signal of the switch circuit from the signal source is switched to the signal source so as to supply to the speaker. 2. The in-vehicle audio device according to claim 1, wherein the another audio signal from the signal source is supplied to the speaker when the count of the timer reaches the predetermined value. In the case, when the detection signal of the detection circuit indicates that the reception level of the broadcast has become higher than the predetermined value, the switch circuit is switched to the reception circuit side to transmit the audio signal from the reception circuit. An in-vehicle audio device to be supplied to the speaker.