JPH0955642A - Radio receiver - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate the need for updating preset by the user by providing a silence detection means and a preset update means to the receiver and storing automatically a broadcast station with excellent reception state to a preset memory at all times by using a silence period. SOLUTION: A silence detection section 51 detects a silence state and when the silence state is consecutive for a prescribed time or over, a preset update section 52 discriminates that the processing is enable within the silence period for update processing. A preset frequency in the preset memory 7 is read in the 1st processing and the frequency is read and the reception acceptance of a broadcast station of the frequency is discriminated and the result is stored in a memory 16. A non-stored frequency is received in the memory 7 in the 2nd processing and the reception acceptance of the broadcast station of the frequency is discriminated and the frequency whose reception is discriminated to be enable for the broadcast station and the level of the electric field strength signal are stored in the memory 16. In the 3rd processing, a preset update object frequency stored in the memory 16 in the 2nd processing is written in the memory 7 in place of a reception disable frequency stored in the memory 16 in the 1st processing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radio receiver, and more particularly to an on-vehicle radio receiver having a preset function and an automatic tuning function.

[0002]

2. Description of the Related Art Generally, a radio receiver has a preset function and an automatic channel selection function in order to reduce operation.
The preset function has a rewritable memory that stores frequencies, that is, a preset memory. By storing the frequency of the broadcasting station of the tuning target in this preset memory as the tuning target frequency, The received signal is received in one scan. In addition, the automatic tuning function scans the broadcast frequency band of the tuning target, and automatically determines whether or not the reception target signal can be received based on the value of the electric field strength signal level or the intermediate frequency with respect to the reception target signal, and reception is possible. The frequency of the received signal of the broadcasting station is searched by one scanning. As a function of storing the frequency in the preset memory, for example, Japanese Patent Laid-Open No. 63-260217 (reference 1) or Japanese Utility Model Publication 3-4.
There is a so-called auto preset process using an automatic channel selection device such as the radio receiver described in Japanese Patent No. 33 (reference 2). In the auto-preset process, all frequencies in the receivable frequency band are received one by one, and it is judged whether or not the reception signal of the frequency corresponding to each broadcasting station can be received. In the order of increasing electric field strength signal level (good reception status), the process of writing in the preset memory as the tuning target frequency is automatically performed. As a result, the user does not need to select the broadcasting stations having a good reception state one by one and store them in the preset memory, and can store the broadcasting stations having a good reception state in the preset memory by one scanning.

In the case of an on-vehicle device, when the receiving place is moved while the tuning target frequency is stored in the preset memory, the stored reception condition of the tuning target frequency is deteriorated. An operation to update is required. As a measure against this, for example, the radio receiver described in Document 2 stores the broadcast station in its service area in memory when it is not in the broadcast receiving mode, and updates the memory content at every predetermined time. As a result, the contents of the preset memory can be automatically updated in response to changes in the reception state without hindering the user from listening to the radio.

Referring to FIG. 18 showing a block diagram of a conventional radio receiver described in Document 2, this conventional radio receiver has an antenna 1 for capturing an incoming radio wave and inputting a reception signal R to an automatic channel selecting device 2, An automatic tuning device 2 that performs automatic tuning and frequency-converts the received signal R that has been selected, and outputs a radio audio signal AR; and a key that the user operates to input an instruction to the microcomputer of the automatic tuning device. 6 and radio voice AR,
A switcher 1 which selects one of the program signals of the compact disc CD and the tape TP and outputs the audio signal AF.
2, an amplifier 8 that amplifies the audio signal AF and outputs the amplified audio signal AP, a mute circuit 10 that stops the output of the amplified audio signal in response to the supply of the mute control signal M, and is driven by the amplified audio signal AP. Speaker 11 for converting to voice
And a preset memory 7 for storing the frequency of the broadcasting station targeted for automatic tuning, and a timer 17 controlled by the microcomputer 5.
With.

The automatic tuning device 2 is a tuner 3 for tuning and receiving the received signal R and outputting a radio audio signal AR.
, PLL circuit 4 for tuning control of tuner 3, and key 6
A microcomputer 5 for control that performs processing corresponding to the instruction input in step 1 and auto preset processing
And a memory 16 for storing the reception availability data of the broadcasting station whose reception availability has been determined by the microcomputer 5.

Next, the operation of the conventional radio receiver will be described with reference to FIG.
The PLL circuit 4 is set based on the reception target frequency. PL
The L circuit 4 controls an internal frequency such as a local oscillation frequency of the tuner 3, and the tuner 3 frequency-converts the reception signal R input from the antenna 1 using this frequency, and the radio sound signal AR to the switcher 12. Output. Further, the tuner 3 supplies the electric field strength signal SD and the intermediate frequency signal IF of the received signal R corresponding to the selected frequency to the microcomputer 5. Based on these two signals SD and IF, the microcomputer 5 judges whether or not the broadcasting station corresponding to the received signal R can be received, and stores the reception / non-reception data of the judgment result in the memory 16.

The switcher 12 is controlled by the switching signal L of the microcomputer 5 and selects one of the program signals of the compact disc CD, the radio audio signal AR and the tape TP and outputs it as an audio signal AF. Amplifier 8
Outputs the amplified audio signal AP to the mute circuit 10 by amplifying the audio signal AF. The mute circuit 10 is controlled by the mute control signal M of the microcomputer 5, and outputs the amplified audio signal AP supplied from the amplifier 8 as it is or stops the output. The speaker 11 is a mute circuit 10
The amplified audio signal output from is converted into audio and output. Under the control of the microcomputer 5, the preset memory 7 reads and writes the frequency of the broadcasting station targeted for automatic tuning as preset data, as will be described later. The timer 17 is controlled by the microcomputer 5.

Next, the conventional auto-preset processing operation will be described with reference to FIG. 19 which shows the auto-preset processing in a flow chart. First, when the content of the preset memory 7 is updated while listening to the radio, Audio is interrupted during this process. To avoid this, the microcomputer 5 automatically updates the contents of the preset memory 7 when the selection input of the switcher 12 is other than the radio audio signal AR as follows.

For example, the user operates the key 6 so as to select the compact disc CD as the input of the switcher 12. The microcomputer 5 switches the input of the switcher 12 and resets the timer 17 (step P2). When the timer 17 has passed 10 minutes (step P3), the auto preset process is started (step P4), and when the process is finished, the timer 17 is restarted until the input of the switcher 12 is set to the radio audio signal AR (step P1). Reset and repeat the auto preset process every 10 minutes.

[0010]

The above-mentioned conventional radio receiver automatically updates the preset memory when the radio is not listening to avoid interruption of the voice during the updating process. When the reception condition of the broadcast radio wave corresponding to the preset frequency stored in the memory is deteriorated and the user selects the preset frequency,
However, there is a drawback that the data is received in a poor reception condition.

It is an object of the present invention to provide a radio receiver which automatically updates the contents of the preset memory even while listening to the radio so that a broadcast in a good reception state can be selected at all times.

[0012]

The radio receiver of the present invention is rewritable by searching the reception band, selecting a reception frequency above a certain level, and storing the selected reception frequency information as a plurality of preset frequencies. A preset memory, a tuner that outputs an electric field strength signal corresponding to the received signal level, and a control unit that controls the tuning frequency of this tuner are used to automatically search for a broadcasting station using the preset frequency and receive the received signal. In a radio receiver including an automatic channel selecting device that outputs an audio signal and an audio amplifier circuit that amplifies the received audio signal to a predetermined level and outputs an audio signal, the control unit corresponds to a broadcasting program being listened to. Silence detection means for detecting a silence state in which the level of the voice signal is below a predetermined fixed level and outputting a silence detection signal; In response to the supply of the signal is configured by a preset updating means for updating the preset frequency silent period is a period of the silent state.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Next, referring to FIG. 1, a first embodiment of the present invention is shown in FIG. 18 in which components common to those in FIG. The radio receiver of the present embodiment has an antenna 1 common to the conventional one,
In addition to the key 6, the amplifier 8, the mute circuit 10, the speaker 11, the preset memory 7, and the timer 17, the silence detecting unit 51 that detects the silence state of the audio signal AP instead of the automatic channel selecting device 2. And a preset updating unit 52 for updating the preset frequency stored in the preset memory 7 during the silent period which is the period of the silent state.
The automatic channel selection device 2A including A and the A / D conversion circuit 9 for converting the amplified audio signal AP into a digital audio signal N and supplying the digital audio signal N to the microcomputer 5A of the automatic channel selection device 2 are provided.

Next, the operation of this embodiment will be described with reference to FIG.
A outputs the audio signal AF corresponding to the received signal R received by the antenna 1. The amplifier 8 amplifies the audio signal AF and supplies the amplified audio signal AP to the mute circuit 10 and the A / D conversion circuit 9. The A / D conversion circuit 9 uses the amplified audio signal A
P is converted into a digital audio signal N and supplied to the microcomputer 5A. The microcomputer 5A determines the silence state from the digital audio signal N supplied from the silence detecting section 51, and the preset updating section 52 updates the preset memory during the silence state period. In the embodiments described below, the silence detecting section 51 and the preset updating section 52 are included in the software of the microcomputer 5A, and are represented by the microcomputer 5A unless otherwise specified.

Referring to FIG. 2A which is a time chart showing the timing relationship between the amplified audio signal AP and the mute control signal M according to the present embodiment, the silence determination AT1 is signal AP.
It is the waiting time from the silent state transition to the output stop of the mute circuit 10. The pre-mute T2 is a waiting time from the output stop of the mute circuit 10 to the frequency setting T3. The frequency setting T3 is a frequency setting time for the PLL circuit 4 of the microcomputer 5A. PLL lock T4 is PLL circuit 4
Is the internal frequency stabilization time of the tuner 3 to be controlled.
The electric field strength check T5 is a confirmation time of the level of the electric field strength signal SD. The intermediate frequency check T6 is a confirmation time of the value of the intermediate frequency signal IF. The post mute T7 is a waiting time from the frequency setting by the frequency setting T3 to the release of the output stop of the mute circuit 10. The frequency setting T3 and the PLL lock T4 are reception processes, and the electric field strength check T5 and the intermediate frequency check T6 are processes for determining whether the broadcasting station can receive or not.

Next, the operation of the automatic preset update processing of the present embodiment will be described with reference to FIG. 3 which is a flowchart showing the automatic preset update processing of the circuit of FIG. Have time to become.
The silence detector 51 (hereinafter, the microcomputer 5A) detects this silence state, and when this silence state continues for a certain time or more,
The preset update unit 52 (hereinafter referred to as the microcomputer 5A) determines that the processing is possible within the silent period and performs the update processing. In the present embodiment, for the sake of convenience of explanation, it is assumed that the above-mentioned fixed time is 20 ms, and
When the silent state continues for more than ms, update processing is performed (steps S1 and S2). In order to end the process during the silent period, the update process is divided into three processes as described below (step S3). In the first update processing, one frequency in the preset memory 7, that is, a preset frequency is read, the preset frequency is received, the reception possibility of the broadcasting station of the frequency is judged, and the result is stored in the memory 16 ( Step S4). The second update process is
One frequency that is not stored in the preset memory 7 is received, the reception possibility of the broadcasting station of that frequency is judged, and the frequency judged to be receivable of this broadcasting station and the level of the electric field strength signal SD are preset update candidate frequencies. Is stored in the memory 16 (step S5). In the third update process, the preset update candidate frequency stored in the memory 16 in the second update process is written in the preset memory 7 instead of the unreceivable preset frequency stored in the memory 16 in the first update process (step S9). ). 1st and 2nd update processing is 1
The reception state of one frequency is checked in the processing during the silent period (steps S2 to S7), and this is repeated for each silent period, and is performed for all receivable frequencies.

More specifically, the microcomputer 5A is an A / D
The digital voice signal N is input from the conversion circuit 9 and the level of this signal N is monitored (step S1). Step S
When it is determined that the sound is in the silent state in 1, the timer 17 is reset, and when the silent state continues for 20 ms or more, the auto preset updating process is started. Next, the microcomputer 5A outputs the mute control signal M, and the mute circuit 10 stops the output of the amplified audio signal AP to the speaker 11 in response to the supply of the mute control signal M (step S2). Either the first or second update processing (step S3) is performed only once. First, the first updating process is performed to check all preset frequencies stored in the preset memory 7. As a result, when there is no unreceivable frequency of the broadcasting station, the first update process is performed again from the next time, and when there is an unreceivable frequency of the broadcasting station, the second update process is performed from the next time and the broadcasting is performed. Search for the receivable frequency of the station. next,
The frequency is returned to the frequency being listened to by the user for reception (step S
6). Next, the microcomputer 5A stops the output of the mute control signal M, and in response to the stop of the supply of the signal M, the mute circuit 10 outputs the audio signal AP (step S7). Second
When the updating process of (3) is finished (step S8), the third updating process (step S9) is performed, and the auto preset updating process is finished. The above process is repeated.

Next, the processing of the second embodiment of the present invention having the same configuration as that of FIG. 1 but different in the automatic preset update processing method is given the same reference characters / numbers as those of FIG. Referring to FIG. 4 similarly showing in a flow chart, the difference between this embodiment and the above-described first embodiment is that
Before the end of the processing during the silent period, the processing for confirming the silent state B of the sound of the broadcasting station being listened to is included (step S10).

Referring to a timing chart showing the timing relationship between the amplified audio signal AP and the mute control signal M of the present embodiment, in addition to T1 to T37 of the first embodiment, the audio of the broadcasting station being listened to The confirmation time T8 of the voiced state is added.

The operation of this embodiment will be described with reference to FIG. 4. In the above-described first embodiment, the first or second updating process is performed only once during one silent period. After finishing the process, the broadcast may still be in silence. However, in the first embodiment, even if there is another processable time during this silent period, the process is terminated once and the silent period of the broadcast is detected again from the beginning. In the present embodiment, at the end of the processing during the silent period, it is confirmed that the broadcast program being listened to is in the silent state, and the processing is repeated until it becomes the voiced state.

The microcomputer 5A confirms the digital audio signal N output from the A / D conversion circuit 9 (step S10) before canceling the audio output stop (step S7). If there is no sound, the broadcasting station of the next frequency is checked, and if there is a sound, the stop of voice is released, and this processing ends.

Next, the processing of the third embodiment of the present invention having the same configuration as that of FIG. 1 but different from the automatic preset update processing method will be described. Components common to those of FIG. 3 will be denoted by common reference characters / numerals. Referring to FIG. 5 similarly showing a flowchart, the difference between this embodiment and the above-described first embodiment is that
This is to include a process of setting the number of stations for confirming whether or not the broadcasting station can be received in one silent period (steps S13 to 218) and a process of repeating the set number of stations during a silent period (step S19).

The operation of this embodiment will be described with reference to FIG. 5. In the above-described second embodiment, when the availability of reception of two or more broadcasting stations is confirmed in one silent period,
It was necessary to check the silence state by receiving the broadcasting station that the user was listening to once. Therefore, the time of the silent period is predicted on the basis of the data of the past silent period, and the number of confirming stations of the reception possibility of the broadcasting station is set in the next silent period. In the present embodiment, it is assumed that the number of confirmed stations is set at a time that is one half of the estimated time, and whether or not the broadcasting station is receivable for a plurality of frequencies is confirmed in one silent period.

The microcomputer 5A inputs the audio signal N from the A / D conversion circuit 9 and detects the change in the silent period / voiced period (step S13). When a change in the silent period / voiced period is detected in step S13, the following process is performed. The silent time from the change of the voice signal N from the voiced state to the voiceless state to the change to the voiced state again is measured using the timer 17 (step S14). The measured silent time is stored in the memory 16 (step S15). Based on the past silence time data stored in the memory 16, a predicted time for the next silence period is set (step S16). For example, if a silent period of 100 ms or more has continued in the past, the predicted time is set to 100 ms. The number of broadcast stations capable of confirming whether or not reception is possible is set at a time half of the set estimated time and stored in the memory 16 (step S17). For example, if the predicted time is 100 ms, the number of broadcast stations that can be confirmed is set within 50 ms. After that, the update processing steps S3 to S5 during the silent period are repeated by the number of stations stored in the memory 16 (step S19).

Next, referring to FIG. 6, which shows a fourth embodiment of the present invention in the same manner as the block with common characters attached to the same components as in FIG. 1, the present embodiment shown in this drawing is shown. The difference from the above-described first embodiment of the radio receiver is that it is provided with a voice analysis circuit 18 for analyzing the frequency characteristic of the amplified voice signal AP.

The voice analysis circuit 18 detects the low level of the voice signal AP,
LPF19, which is a filter for medium and high frequency bands,
The MPF 20 and HPF 21 and the A / D conversion circuit 22 are provided.

Each filter LPF19, MPF20, HP
The F21 inputs the audio signal AP and outputs it by dividing it into low, medium and high frequency bands. The A / D conversion circuit 22 A / D-converts the output signals of the LPF 19, MPF 20, and HPF 21, and outputs digital audio signals N1, N2, N3, respectively.

Next, referring to FIG. 7 in which the processing of the present embodiment is also shown in a flow chart with common reference characters / numerals attached to the components common to those of FIG. The difference from the first embodiment is the setting process of the number of broadcast stations (steps S20 to 224) for confirming the reception availability in one silence period corresponding to the contents of the broadcast program, and the silence for the set number of stations. Update processing steps S3 to S5 during the period
And the process of repeating (step S25).

Next, the operation of this embodiment will be described with reference to FIGS. 6 and 7. The duration and frequency of the silent period differ depending on the content of the broadcast program. In programs such as news and lectures that mainly focus on human talk, the duration of silence is long and frequent. Further, in the case of a music program, the duration of silence is short and the frequency is low. Therefore, in the present embodiment, the content of the program is determined from the frequency characteristics, and the number of confirming broadcast stations for reception availability is set within one silent period based on the content of the program.

FIG. 8 shows an example of frequency characteristics of human voice and music programs in comparison with the center frequencies fL, fM, and fH of the LPF 19, MPF 20, and HPF 21, respectively.
Referring to (A) and (B), the human voice has an overwhelmingly high level of the mid-range frequency fM as compared with the low-range and high-range frequencies. On the other hand, music has the highest level in the middle range, but the level difference between the low range and the high range is small. Therefore, in the present embodiment, the levels of the output audio signals N1, N2, N3 of the audio analysis circuit 18 are compared, and the level of the signal N2 is the maximum, and N2 and N3 are the same.
If the level ratio between 1, and N2 and N3 is not more than double in dB value, this program is judged to be music, and the number of receivable / non-confirmable stations within one silent period is set from this program.

First, the microcomputer 5A uses the voice analysis circuit 18
The audio signals N1, N2, and N3 of the respective frequency bands are input from and the respective levels are judged (step S2).
0). For the determination of this level, for example, an averaging method or the like is used. Next, the levels of the audio signals N1 to N3 in each frequency band are compared to determine the program content (step S2).
1). For example, the levels of N1, N2 and N3 are 30
If it is dB, 45 dB, 15 dB, the level of N2 is the maximum and the ratio of the levels of N2 and N3 is 3 times, but the level ratio of N2 and N1 is 1.5 times. Judge that the content is music. Next, the judgment result is stored in the memory 16 (step S2). Next, the number of confirmable reception stations that can be received in one silent period is set according to the program contents stored in the memory 16 (step S23) and stored in the memory 16 (step S2).
4). For example, if the program stored in the memory 16 is music, it is determined that the duration of the silent period is short, and it is set that only one station can be received or not within one silent period.
Next, the update processing steps S3 to S5 during the silent period are repeated by the number of stations stored in the memory 16 (step S2).
5).

Next, the processing of the fifth embodiment of the present invention having the same configuration as that of FIG. 1 but different in the automatic preset update processing method is given the same reference characters / numbers as those of FIG. Referring to FIG. 9 similarly showing a flowchart, the difference between this embodiment and the above-described first embodiment is that
Having a process of storing the electric field intensity signal SD in the memory 16 (step S26), and the electric field intensity signal stored in the memory 16 instead of the branch determination process step S3 of steps S4 and S5 for starting the second update process. The step S27 is to make a judgment based on the change in SD.

The operation of the present embodiment will be described with reference to FIG. 9. As is well known, the changing mode of the electric field strength signal SD differs depending on the cause of deterioration of the reception state of broadcast radio waves.
Referring to FIG. 10 showing an example of changes in the electric field strength signal SD, FIG. 10A shows a case where the electric field strength signal SD gradually decreases due to an increase in the distance from the broadcasting station and the change is gradual. (B) shows a case where it is suddenly shielded by a radio wave obstacle like when entering a tunnel, and the electric field strength signal SD shows a sudden change. In the present embodiment, the radio wave state at the reception point is determined from the manner of change of the electric field strength signal SD, and the start / non-start of the second update process is determined. For convenience of explanation, in the present embodiment, the electric field strength signal SD
If it falls within the receiving time judgment level from 30 dB to 10 dB within a fixed time of 500 ms, it is judged that it has temporarily moved to a place with bad reception conditions, and the start / non-start judgment of the update processing is performed. .

First, the microcomputer 5A inputs the level of the electric field strength signal SD of the broadcast being listened to and stores it in the memory 16 (step S26). The microcomputer 5A refers to the level of the electric field strength signal SD stored in the memory 16 when it finds a frequency of poor reception among the preset frequencies stored in the preset memory 7 in the first update processing,
If the reception state of the broadcasting station being listened to is abruptly deteriorated, the second updating process is not started (step S27). For example, if it is assumed that the power is rapidly decreasing from 35 dB to 10 dB in 500 ms, in step S27, the first
Update process.

Referring to FIG. 10 again, an example of determination of the start / non-start of the second updating process of step S27 will be described. In the case of (B), the electric field strength signal SD drops sharply, so As described above, it is determined that the mobile station has temporarily moved to a place where reception is poor, and other broadcast stations do not start the second update process because reception is poor. In the case of (A), since the electric field strength signal SD is gradually decreased, it is determined that the reception state is deteriorated due to the distance from the listening broadcasting station as described above, and other broadcasting stations can search for it. The update process of No. 2 is started.

Next, referring to FIG. 11, which shows a sixth embodiment of the present invention in the same manner with blocks in which the constituent elements common to those of FIG. 1 are designated by common characters, the embodiment of the present invention shown in this drawing is shown. The difference between the radio receiver of the present invention and the first embodiment described above is that
Audio signal AP by volume control signal P from the microcomputer 5A
That is, a volume control circuit 23 for controlling the level of is provided.

Further, referring to FIG. 12 in which the processing of this embodiment is also shown in a flow chart with common reference characters / numerals attached to the same components as those of FIG. 3, the above-mentioned first embodiment of this embodiment will be described. The difference from the first embodiment is the process of setting the level of silence determination (steps S28 and S29) and the process of determining the silence state at the set level (step S30).
Is to include and.

Next, the operation of the present embodiment will be described with reference to FIGS. 11 and 12, because the range of the listening voice level of the user varies depending on the reception state and the volume.
In the present embodiment, the setting of the silence determination level is changed depending on the reception state or the volume. First, the microcomputer 5A
The electric field strength signal SD of the frequency being listened to is measured, and the silence determination level corresponding to it is set (step S28).
Further, the silence determination level is set corresponding to the volume value set by the user with the key 6 (step S29). The microcomputer 5A compares the set level with the level of the audio signal N, and when the set level is higher, determines that there is no sound (step S30).

An example of setting the silence determination level will be described. When the reception condition is good, the entire sound is loud, so it is determined that there are not too many small sounds, and the silence determination level is increased. On the other hand, when the reception condition is bad, the sound level is low as a whole, so the silence determination level is reduced. Further, when the listening volume is low, only a loud sound is heard, so that the silence determination level is increased. On the contrary, when the listening volume is high, even a small sound is heard, so the silence determination level is reduced.

Next, the processing of the seventh embodiment of the present invention having the same configuration as that of FIG. 1 but different in the automatic preset update processing method is given the same reference characters / numbers as those of FIG. Similarly, referring to FIG. 13 which is a flowchart,
The difference of this embodiment from the above-described first embodiment is that it has a branching process (step S30) that divides the second update process (step S5) into two processes (steps S31 and S32). Instead of the third update process (steps S8 and S9) at the end of the update process, after the end of the search of the broadcast station by the field intensity signal SD, the frequency determined to be the broadcast station is set to the magnitude of the field intensity signal SD. This is to have processing (steps S34, S35) for rearranging in order.

The operation of this embodiment will be described with reference to FIG. 13. In the above-described first to sixth embodiments, since the processing is divided for each silent period, if the processing amount is large, the It will take. In the present embodiment, first, only the electric field strength signal SD is searched and then the electric field strength signal SD is searched.
From the largest one, a search is performed to confirm whether or not the broadcasting station is receivable at the intermediate frequency IF. First, the preset memory 7 receives one unstored frequency, inputs the electric field strength signal SD of that frequency, determines whether or not the broadcasting station is receivable only by this signal SD, and when it is determined that reception is possible, the memory is 1
The frequency and SD level are stored in 6 (step S3).
1). When the search for all the frequencies is completed in step S31 (step S34), the frequencies stored in the memory 16 in step S31 are rearranged in the order of the level of the electric field strength signal SD (step S35). Next, step S
The frequencies rearranged in 35 are set in order from the highest SD to 1
When the stations are received and the intermediate frequency IF is confirmed and it is determined that the frequency is receivable, the frequency is stored instead of the unreceivable preset frequency stored in the preset memory 7 (step S32). The process ends when there is no preset frequency that cannot be received.

Next, referring to FIG. 14, which shows the eighth embodiment of the present invention in the same manner as the block in which the constituent elements common to those of FIG. 1 are designated by common characters, the embodiment of the present invention shown in this drawing is shown. The difference between the radio receiver of the present invention and the first embodiment described above is that
It is provided with a read-only memory (ROM) 24 in which frequencies of broadcasting stations that can be received by region are recorded.

Further, referring to FIG. 15 which is a flow chart in the same manner as in FIG. 3, the components common to those in FIG. 3 are designated by common reference characters / numerals. The difference from the first embodiment is that the second updating process includes step S36 of searching for a frequency of a receivable broadcasting station in the area, instead of step S5.

The operation of this embodiment will be described below.
In the above-described embodiments, it takes time because the broadcasting station is searched for all frequencies. In the present embodiment, the frequencies of the broadcasting stations in the receiving area are prioritized as the receivable stations and are searched. That is, the frequencies of receivable broadcasting stations for each region are stored in the ROM 24 in advance, and the search is performed only for those frequencies. First, the frequencies of broadcasting stations stored in the ROM 24 of the region currently being identified are received one by one, and the reception availability is confirmed by the electric field strength signal SD and the intermediate frequency IF. And the electric field strength signal SD are stored (step S3).
6). The region can be specified by, for example, comparing the frequency of the broadcasting station determined to be receivable with the frequency of the broadcasting station for each region stored in the memory 22, or only by this comparison, the region having the broadcasting station of the same frequency can be identified. If there is more than one, it cannot be specified.

In the sixth to eighth embodiments described above, step S31 of first searching for a frequency having a large electric field strength,
ROM 24 that stores frequencies of receivable broadcasting stations by region
By using, the search processing time can be shortened. For example, the search target frequency range is 76.0 MHz to 89.9 M.
In Hz, if the search step is 0.1 MHz, 140
You will search for the frequency of the station. At this time, if there are 10 receivable broadcasting stations by region, the search can be performed at a speed of 1/14.

Next, referring to FIG. 16, which shows the ninth embodiment of the present invention in the same manner with blocks in which the constituent elements common to those of FIG. 1 are designated by common characters, the present embodiment shown in this drawing is shown. The difference between the radio receiver of the present invention and the first embodiment described above is that
An A / D conversion circuit 25 for converting the analog audio signal AP into a digital audio signal DP, and the digital audio signal DP
Delay circuit 26 which delays the delay time and controls the delay time by the delay control signal O from the microcomputer 5A to generate the delayed audio signal D.
And a D / A conversion circuit 27 for converting the delayed audio signal D into the analog audio signal DA again.

Further, referring to FIG. 17 in which the processing of the present embodiment is also shown in a flow chart with common reference characters / numerals attached to the components common to those of FIG. 3, the above-mentioned first embodiment of the present embodiment will be described. The difference from the first embodiment is that it includes a process of controlling the delay time (steps S37 to 239, 241) and a process of determining interruption of the search of the broadcasting station during the silent period (step S40). .

Next, the operation of this embodiment will be described with reference to FIGS. 16 and 17. In each of the above embodiments, when the silent period is short, the processing time during the silent period is shorter than the actual silent period. Will be longer. In the present embodiment, a delay circuit is inserted in the output audio signal to perform processing during the silent period until the delayed audio signal is output.
Here, the voice is delayed by 22.6 μs every 1 ms, and the processing during the silent period is performed while the voice input to the delay circuit is being output.

First, the microcomputer 5A controls the delay circuit 26 so as to maximize the delay, and every 1 ms (step S3).
8) The audio signal DP is delayed by 22.6 μs (step S39). When the delay circuit 26 reaches the maximum delay value, the delay control is stopped and the silence detection is started (step S3).
7). Next, the processing during silence is repeated while the delayed audio signal D is being output from the delay circuit 26. Microcomputer 5A
Receives the frequency being listened to by the user before the audio signal D of the delay circuit 26 disappears (step S40), and cancels the output stop of the mute circuit 10. The delay circuit 26 is controlled to set the delay time to 0 when the delayed audio signal D is in the silent state.
To output the audio signal DP as it is (step S
41, FIG. 17). The above process is repeated.

In addition, in the first to ninth embodiments, the microcomputer 5A determines the silent state, but instead of the A / D conversion circuit 9, a silent detection circuit composed of a comparator or the like is used. As a result, the microcomputer 5A can determine the difference between voiced / silent only by the high / low level.

[0051]

As described above, the radio receiver of the present invention comprises the silence detecting means and the preset updating means,
Since the preset update process is performed using the silent period, the broadcasting station with a good reception condition is automatically stored in the preset memory, which eliminates the need for the user to perform the preset update operation, which has the effect of reducing the operation. .

[Brief description of drawings]

FIG. 1 is a block diagram showing a first embodiment of a radio receiver of the present invention.

FIG. 2 is a time chart showing an example of operations in the radio receivers of the first and second embodiments.

FIG. 3 is a flowchart showing an example of operation in the radio receiver according to the first embodiment.

FIG. 4 is a flowchart showing an example of an operation in the radio receiver of the second exemplary embodiment of the present invention.

FIG. 5 is a flowchart showing an example of operation in the radio receiver according to the third exemplary embodiment of the present invention.

FIG. 6 is a block diagram showing a fourth embodiment of a radio receiver of the present invention.

FIG. 7 is a flowchart showing an example of operation in the radio receiver of this embodiment.

FIG. 8 is a characteristic diagram showing an example of frequency characteristics of human voice and music programs.

FIG. 9 is a flowchart showing an example of an operation in the radio receiver of the fifth exemplary embodiment of the present invention.

FIG. 10 is a diagram showing an example of how the electric field strength signal changes.

FIG. 11 is a block diagram showing a sixth embodiment of the radio receiver of the present invention.

FIG. 12 is a flowchart showing an example of operation in the radio receiver of this embodiment.

FIG. 13 is a flowchart showing an example of operation in the radio receiver of the seventh exemplary embodiment of the present invention.

FIG. 14 is a block diagram showing an eighth embodiment of the radio receiver of the present invention.

FIG. 15 is a flowchart showing an example of operation in the radio receiver according to the present embodiment.

FIG. 16 is a block diagram showing a ninth embodiment of a radio receiver of the present invention.

FIG. 17 is a flowchart showing an example of operation in the radio receiver according to the present embodiment.

FIG. 18 is a block diagram showing an example of a conventional radio receiver.

FIG. 19 is a flowchart showing an example of operation in a conventional radio receiver.

[Explanation of symbols]

 1 Antenna 2, 2A Automatic Channel Selector 3 Tuner 4 PLL Circuit 5, 5A Microcomputer 6 Key 7 Preset Memory 8 Amplifier 9, 9, 22, 25 A / D Converter Circuit 10 Mute Circuit 11 Speaker 12 Switcher 16 Memory 17 Timer 18 Voice Analysis Circuit 19 LPF 20 MPF 21 HPF 23 Volume adjustment circuit 24 ROM 26 Delay circuit 27 D / A conversion circuit 51 Silence detection section 52 Preset update section

Claims (10)

[Claims] 1. A rewritable preset memory for searching a reception band to select a reception frequency above a certain level and storing the selected reception frequency information as a plurality of preset frequencies, and an electric field strength corresponding to the reception signal level. An automatic tuning apparatus that includes a tuner that outputs a signal and a control unit that controls the tuning frequency of the tuner, and that automatically searches for a broadcasting station by using the preset frequency and outputs a reception audio signal corresponding to a reception signal, and In a radio receiver including a voice amplifier circuit that amplifies a received voice signal to a predetermined level and outputs a voice signal, the control unit is configured such that the level of the voice signal corresponding to a broadcast program being listened to is a predetermined level. Silence detecting means for detecting a silence state of a level or less and outputting a silence detection signal, and a period of the silence state in response to the supply of the silence detection signal. Radio receiver; and a preset updating means for updating the preset frequency silence period is. 2. A silence period determining means for determining that processing is possible and outputting an update process start signal when the preset updating means responds to the supply of the silence detecting signal when the silent period continues for a predetermined time or more, The first reception signal of the first frequency corresponding to each of the preset frequencies is received, and whether or not each first reception signal is receivable is determined by using the electric field strength signal, and the first unreceivable signal is received.
A preset reception possibility determining means for performing a first process of selecting a first frequency corresponding to the reception signal, and a second reception signal of a second broadcasting station of a second frequency other than the preset frequency. Whether or not the second received signal can be received is determined using the electric field strength signal, and when it is determined that the second received signal can be received, the second frequency and its electric field strength level are selected as preset update candidates. Preset update candidate selection means for performing a second process, and preset memory for performing a third process of storing the second frequency of the preset update candidate in the preset memory instead of the unreceivable first frequency. The radio receiver according to claim 1, further comprising rewriting means. 3. The radio receiver according to claim 1, further comprising an A / D converter that digitally converts the audio signal and supplies the digital audio signal to the control unit. 4. A voice analysis circuit for outputting first, second and third frequency signals corresponding to respective frequency components of the low frequency band, the middle frequency band and the high frequency band of the voice signal, the control circuit comprising: Further, there is further provided level comparison silence prediction means for judging the program content corresponding to the audio signal from the result of comparison of the levels of the first to third frequency signals and predicting the silent period which is the period of the silent state from the program content. The radio receiver according to claim 1, further comprising: 5. A volume adjusting circuit for controlling a volume value which is a level of the audio signal in response to supply of a control signal from the control section, wherein the silence detecting means corresponds to the volume value. The radio receiver according to claim 1, wherein the fixed level corresponding to the silent state is variable. 6. The preset updating means comprises a voiced state confirmation means for confirming that the voice signal is in a voiced state at the end of one of the first and second processes. The radio receiver according to claim 2. 7. A timer for measuring the duration of a silent period of the audio signal is provided, wherein the preset updating means is configured to perform the first and the first operations for each time based on the past duration data of the silent period. Two
3. The radio receiver according to claim 2, further comprising processing number setting means for setting the number of times of the processing. 8. The preset update means stores the level of the electric field intensity signal corresponding to the received signal being listened to as a reference level, and when the first received signal is a poor reception in the first process, 3. The radio receiver according to claim 2, further comprising an electric field strength change determination means that compares the reference level with the reference level and executes the first process again when the level drops below a predetermined level within a predetermined time. . 9. A read-only memory storing a third frequency of a broadcasting station which can be received by region, wherein the preset updating means receives a reception signal of the third frequency instead of the second frequency. The radio receiver according to claim 2, further comprising a second preset update candidate selection unit that performs the second processing by performing the above. 10. An audio signal delay means for delaying the audio signal, the delay time of which is controlled in response to the supply of the delay control signal from the control unit, and the first and second processes being performed within the delay time. The radio receiver according to claim 1 or 2, characterized in that: