JPH1051271A - Receiver - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a processing time for an initial setting processing of a preset memory. SOLUTION: In the case of conducting an initial setting processing of a memory 30 in a receiver 11 having a preset memory function, at first a time constant of a low-pass filter 28 is decreased to detect a reception electric field strength for each broadcast frequency over an entire frequency band, where broadcast wave frequencies exist. Then the time constant of the filter 28 is restored, and in the case of a reception of a broadcast station frequency whose reception electric field strength is a prescribed level or over, whether or not a frequency of an output signal outputted from an intermediate frequency amplifier circuit 18 is an intermediate frequency is judged. Only when the frequency is intermediate frequency, is it judged that there is any broadcast station using the broadcast station frequency for its transmission, and the reception setting condition of the broadcast station frequency is stored in a memory. Furthermore, in the case that the receiver 11 is a receiver that demodulates and reproduces a served signal to obtain served information, only the reception setting condition for the broadcast frequency of an information server broadcast station sending the service signal is stored in the memory 30.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a receiver having a preset memory function using a memory storing broadcast station frequencies and an auto preset function for automatically setting the contents stored in the memory.

[0002]

2. Description of the Related Art Conventionally, some radio receivers and television receivers have a so-called preset memory function. The preset memory function means that a reception setting condition for receiving broadcast waves of a plurality of broadcast station frequencies is stored in a memory in advance, and when each of these broadcast waves is received, the condition is read out from the memory and each of the receivers is read. This function switches the circuit settings. When the reception setting condition is stored in the memory, the user of the receiver receives the broadcast wave of the reception setting condition simply by operating a preset switch corresponding to each condition in the memory on a one-to-one basis. Can be received by the machine.

[0003] The applicant of the present invention discloses a receiver having a preset memory function in Japanese Patent Laid-Open Publication No. Hei 4-240914, which is capable of receiving signals properly even when the reception position moves and the receivable broadcasting station frequency changes. Propose a radio receiver to do. When a receiver mounted on a vehicle is receiving a broadcast wave from a certain broadcast station, and the received electric field strength of the broadcast wave of this broadcast station is lower than a predetermined level, the receiver is in a reception state. In order to select another broadcasting station having a good broadcast frequency, broadcast waves of a plurality of broadcasting station frequencies stored in the memory are sequentially received. If the user of the receiver selects a broadcast station during the reception process, the broadcast wave of the broadcast station frequency is continuously received thereafter.

[0004] Further, the applicant of the present invention has disclosed Japanese Patent Laid-Open No. 5-12201.
Japanese Patent Application Laid-Open No. 5 (1999) -2005 proposes an audio apparatus having a preset memory scan function for sequentially receiving broadcast waves of a plurality of broadcast station frequencies stored in a memory of a preset memory function at predetermined time intervals. When the acoustic device performs the preset memory scan function, it simultaneously receives a broadcast wave of a broadcast station frequency stored in the memory and detects a received electric field strength at that time.
If the received electric field strength is less than a predetermined level during the reception operation of a certain broadcasting station frequency, for example, in order to prevent sound close to noise from being output for a certain period of time, the reception operation is performed before a certain period of time elapses. The operation is suspended, and the operation proceeds to the next broadcast wave receiving operation.

[0005] In the two receivers having the above-mentioned memory function of the preset memory function, it is necessary to store the reception setting conditions of the receivable broadcast station frequency in the memories in advance and set the memories. . The setting of this memory is automatically performed by the receiver itself, for example, by an initial setting process called an auto preset process.

In this initial setting process, all channels in this band are received over the entire frequency band in which all types of broadcast station frequencies that can be received and demodulated by the receiver can exist. When receiving each channel, first determine whether there is a broadcasting station using the channel, and only when it is determined that there is a broadcasting station, detect the reception electric field strength of the broadcast wave transmitted on the channel and set the reception setting condition. Is stored in memory. The reception electric field strength is used when determining the arrangement order of the reception setting conditions in the memory. The arrangement order is determined so that the reception setting condition of the broadcast wave having the high reception electric field strength is read out with priority.

FIG. 7 is a graph showing a change over time of a detection frequency in a memory initialization processing operation performed in a conventional receiver.

[0008] Broadcast station detection processing for each detection frequency is as follows.
If the receiver is a superheterodyne system, detect the frequency of the signal on the output line of the intermediate frequency signal that is the output line of the intermediate frequency amplification circuit, and determine whether the frequency is the intermediate frequency. Done by The frequency of the signal is detected, for example, by counting the wave number of the signal for 20 to 30 msec. Therefore, the processing time W1 of the broadcast station detection processing for a single detection frequency
Is 20 ms to 30 ms or more.

First, a reception tuning frequency is set in the receiving means from time t0, and the reception frequency is set as the detection frequency which is the broadcast wave frequency of the broadcast wave to be demodulated by the receiver, which is the carrier frequency f1 of the lowest channel. And the frequency f1
Starts the detection of the broadcast station whose frequency is the broadcast station frequency.

Since the broadcast station having the frequency f1 is detected by the above-described processing, the reception electric field strength at the time of reception at the detection frequency from time t1 after the lapse of the processing time W1 from time t0 is detected. When the detection is completed at time t2, the detection frequency is changed to the frequency f2 of the next channel, and the detection of the broadcast station having the frequency f2 is started. Since the broadcast station of the frequency f2 was not detected, when the detection is ended at the time t3 after the lapse of the processing time W1 from the time t2, the detection of the reception electric field strength is omitted, and the detection frequency is further changed to the next frequency f3. The detection of the broadcast station of the frequency f3 is started. Similar detection operations are sequentially performed up to the channel of the maximum frequency.

As described above, in the initialization processing operation of the related art, the broadcast station detection processing is performed only as many times as the number of channels in the entire frequency band. Therefore, the processing time of the initial setting processing is the number of channels times the processing time W1. The channels in the frequency band are 100 (AM) radio broadcasts.
Since there are 0 or more channels, this processing time becomes extremely long.

For example, this receiver is installed in a valley in a mountainous area where there are many stations where the received electric field strength of the broadcast wave is small and the demodulated voice is hard to hear, and in a plain area where there are few stations that are hard to hear. When this initial setting operation is performed, the broadcast station detection processing is performed for the same number of channels in both places. Therefore, the same length of processing time is required when the number of broadcast station frequency reception setting conditions stored in the memory after the initial setting processing is small and large. During the above-described initialization processing operation, it is difficult to demodulate and listen to a certain broadcast wave, so when performing the initialization operation in the mountainous area, the user of the receiver,
It may be evaluated that the result is less than the time when listening was difficult.

JP-A-2-165717 discloses that
A technology related to an in-vehicle electronic tuning receiver having an automatic tracking function using a radio data system is disclosed. In this receiver, when the received electric field intensity of the currently receiving broadcast station decreases while the automobile is running, first, the received electric field intensity of all program stations broadcasting the same program included in the frequency list in the RDS data is detected. Then, the same program station having the maximum received electric field strength is searched. Next, an IF count is performed only for the program station in order to confirm whether the program station can be received at the correct frequency. If the program station is correct, the program station is selected and received. This receiving operation is an operation of searching for a so-called alternative station when the receiving position of the receiver changes over time, and is different from the initial setting operation of the memory of the preset memory function.

Japanese Patent Application Laid-Open Publication No. Sho 63-256021 discloses a technique related to a diversity type narrow band mobile radio. In this radio, first, received electric field strengths detected from outputs of a plurality of receivers having different reception positions are compared, and an output from the receiver having the largest received electric field strength is provided to a subsequent processing device. Next, the frequency is detected by the frequency counter to confirm that the correct frequency is being received. Since this receiver detects the difference in the reception electric field strength of the signal of the same frequency, the reception electric field strength of the broadcast wave of different frequency is detected, and it is appropriate to store the reception setting condition in the memory of the preset memory function. It is different from the device that judges.

[0015] In the receivers and radios of these two publications, the processing by the frequency counter is performed only once. In the initial setting operation of the preset memory function, it is necessary to confirm whether or not all receivable broadcast waves are being received at the correct frequency. Therefore, like these receivers and radios, a single frequency count is used. It is difficult to perform only for the broadcast wave. Therefore, it is difficult to reduce the processing time by the same technique.

Further, Japanese Patent Laid-Open Publication No. Hei 4-307807 discloses a receiving apparatus which performs frequency counting in a short processing time. In this receiving apparatus, the frequency of a broadcast wave whose detected reception electric field strength is equal to or higher than a predetermined reference reception electric field strength is counted. In this frequency counting process, the counting time of the frequency of the intermediate frequency signal is set in two steps, and if the error of the counted frequency is out of a predetermined range within the counting time of the first step, the counting time is further extended. I do.

In this receiver, if the broadcast wave has a reception electric field strength equal to or higher than the reference reception electric field strength, regardless of whether the reception electric field strength is close to the reference reception electric field strength or extremely higher than the reference reception electric field strength, A frequency count process is performed. Therefore, when the memory capacity of the preset memory function is smaller than the capacity capable of storing all the reception setting conditions of the broadcast station frequencies of all the channels in the frequency band, the reception electric field strength is relatively high depending on the reception order of the broadcast waves. In some cases, only the reception setting conditions for a small broadcast wave are stored in the memory, and the reception setting conditions for a broadcast wave having a large reception electric field strength cannot be stored.

[0018]

SUMMARY OF THE INVENTION An object of the present invention is to provide a receiver having a preset memory function, which can reduce the processing time in the memory initialization processing operation.

[0019]

SUMMARY OF THE INVENTION The present invention relates to a receiving means for receiving a signal tuned at a plurality of reception tuning frequencies over the entire frequency band in which a broadcasting station frequency exists, and outputting a received signal;
A memory for storing the reception tuning frequency of the reception means, an electric field intensity detection means for responding to the output of the reception means for detecting a reception electric field intensity for each reception tuning frequency, and an output for receiving the electric field intensity detection means; Receiving frequency detecting means for detecting a receiving tuning frequency at which the level of the received electric field strength is equal to or higher than a predetermined level among the receiving tuning frequencies of all the received signals, responding to the outputs of the receiving means and the receiving frequency detecting means, Each reception tuning frequency detected by the frequency detection means is tuned by the reception means in a predetermined order and received, and the presence or absence of a broadcasting station of the reception tuning frequency is detected from each reception signal, and the reception tuning frequency at which the broadcasting station exists is detected. And a broadcast station detecting means for storing only the information in a memory. According to the invention, the receiver has a so-called preset memory function. The preset memory function is a function of storing reception tuning frequencies respectively corresponding to broadcast station frequencies of a plurality of broadcast waves in a memory in advance, and setting the reception tuning frequency of the receiving unit based on the stored contents in the memory. . The user of the receiver having the preset memory function can operate the key of the keyboard corresponding to the desired broadcast station, for example, by operating the key of the keyboard corresponding to each reception tuning frequency of the memory on a one-to-one basis. Broadcast waves from a broadcasting station can be received. In order to use this preset memory function, it is necessary to store the reception tuning frequency of each broadcast wave or the setting condition of the reception tuning frequency to the receiving means in the memory for a plurality of receivable broadcast waves before using the function. is there. In the receiver of the present invention, the receiver itself automatically performs an initial setting operation of the memory for storing the reception tuning frequency in the memory. When the memory setting processing operation is started, the receiver first sets a plurality of reception tuning frequencies in the receiving means sequentially. As a result, of the output from the antenna of the receiver, the signal component of the frequency tuned corresponding to the set reception tuning frequency is emphasized, and the output is output from the reception unit as a reception signal corresponding to the reception tuning frequency. Is done. This receiving operation is performed over the entire frequency band in which the broadcast station frequency exists. For example, the receiver sequentially sets the reception tuning frequency corresponding to the broadcast station frequency, which is the carrier frequency of all the channels in this frequency band, to the receiving means, and outputs a reception signal at the time of receiving each broadcast station frequency. Let it. Of all these channels, only some channels are used for transmitting broadcast waves.
For example, as described above, when all the channels are received by the receiving unit, the level of the received electric field strength detected at the time of reception of an existing channel not used for transmission of the broadcast wave is caused by the signal amplitude of the broadcast wave, and the level of the received electric field is reduced. It is considered that the level of the received electric field strength detected at the time of receiving the unused idle channel is caused by the amplitude of the noise. Therefore, comparing the levels of the received electric field strength at the time of receiving the existing channel and at the time of receiving the empty channel, it is considered that the level of the existing channel is sufficiently higher than the level of the empty channel. From these facts, it can be determined from the magnitude of the received electric field strength whether each channel is used for transmitting broadcast waves. In the receiver of the present invention, all received signals output from the receiving means are supplied to the electric field strength detecting means, and the level of the received electric field strength at the time of channel reception corresponding to each reception tuning frequency is detected by the means. This detection result is compared with a reference level predetermined by the reception frequency detection means, and only the reception tuning frequency of the channel having the reception electric field strength equal to or higher than the reference level is detected. This reference level is equal to or higher than the reception electric field strength at the time of receiving an idle channel,
In addition, it is set to less than the reception electric field strength at the time of reception of the existing channel. Therefore, only the reception tuning frequency of the existing channel can be detected from the reception tuning frequencies of all the channels based on the magnitude of the reception electric field strength with respect to the reference level. As described above, in the case of detecting the presence or absence of a broadcast wave based on the magnitude of the received electric field strength, when the reception tuning frequency is set to an empty channel adjacent to an existing channel, the broadcast wave of the adjacent existing channel becomes an empty channel. In some cases, the level of the received signal at the time of receiving an empty channel increases due to leakage, and the received electric field strength detected at that time may increase. Also, in the above-mentioned case, even when the noise level of the idle channel is extremely high, the reception electric field strength at the time of receiving the idle channel may increase. At this time, the reception frequency detection means erroneously detects that the channel is an existing channel, even though the channel is an empty channel. In the receiver of the present invention, the broadcast station detecting means detects and confirms that the channels detected by the receiving frequency detecting means are used for transmitting broadcast waves from the broadcast stations.
In the broadcasting station detecting means, first, only the reception tuning frequency detected by the receiving frequency detecting means is set in the receiving means again in a predetermined order, and the receiving means is tuned with the antenna output to output a reception signal. Next, for each received signal, it is detected whether or not there is a broadcast station that uses a channel corresponding to the received tuning frequency for transmitting broadcast waves. Based on the detection result, only the reception tuning frequency of the reception signal in which the broadcasting station exists is stored in the above-described memory. The received tuning frequency stored in this way is used for the preset memory function. The processing time of the reception frequency detection processing performed by the reception frequency detection means for a single reception tuning frequency is longer than the processing time of the broadcast station detection processing performed by the broadcast station detection means for the same reception tuning frequency. In the above-described memory setting process in the conventional receiver, since the broadcast station detection process is performed for every channel in the entire frequency band, the processing time of the memory setting process is long.
In the memory setting process of the receiver according to the present invention, the reception frequency detection process is performed over the entire frequency band to detect channels to be subjected to the broadcast station detection process, and then the broadcast station detection process is performed only on these channels. Therefore, the number of channels to be subjected to the broadcast station detection processing is reduced, and the number of times of performing this processing is reduced. As a result, the receiver of the present invention can shorten the processing time of the memory setting process as compared with the processing time of the conventional receiver.

Further, according to the present invention, the receiving means is a superheterodyne system, and the broadcasting station detecting means detects a frequency of a signal on an output line of an intermediate frequency signal of the receiving means, and a detecting means using a frequency counter. Determining means for determining that a broadcasting station exists only when the determined frequency is a predetermined intermediate frequency. According to the invention, the receiving means of the receiver is a superheterodyne device. In the superheterodyne receiver, the output from the antenna after being tuned to the reception tuning frequency is subjected to frequency conversion processing, and the received signal to be demodulated is converted into an intermediate frequency signal. To perform demodulation processing. At this time,
If the reception tuning frequency set in the receiving means corresponds to the above-mentioned broadcasting station frequency of the existing channel, the frequency of the signal on the output line of the intermediate frequency signal matches the predetermined intermediate frequency. If the reception tuning frequency corresponds to the remaining frequency other than the broadcasting frequency of the existing channel, the frequency of this signal does not match the intermediate frequency. For example, when the reception tuning frequency corresponds to the carrier frequency of a vacant channel adjacent to the existing channel, it is considered that the reception electric field strength is obtained by erroneously detecting the leakage of the broadcast wave of the existing channel adjacent to the vacant channel. Therefore, the frequency of the received signal at this time is significantly different from the carrier frequency of the empty channel. Therefore, when a local oscillation signal for converting the carrier frequency of the vacant channel to the intermediate frequency is mixed with the received signal, the frequency of the converted signal does not become the intermediate frequency. Thus, the frequency of the signal on the output line of the intermediate frequency signal matches the intermediate frequency only when the reception tuning frequency is the broadcasting station frequency of the existing channel used for transmitting the broadcast wave. Therefore,
By examining the frequency of the signal on this output line, the presence or absence of a broadcast station corresponding to the reception tuning frequency can be detected. The broadcast station detecting means of the receiver of the present invention first detects the frequency of the signal on the output line of the intermediate frequency signal of the receiving means by a frequency counter. This detection result is given to the judgment means, and it is judged whether or not the detected frequency is a predetermined intermediate frequency. Only when the detected frequency is the intermediate frequency, the judging means judges that a broadcast station corresponding to the reception tuning frequency exists. The broadcast station detecting means stores the reception tuning frequency in the memory based on the result of the determination. By such a series of processing operations, the presence or absence of a broadcasting station can be reliably and easily detected.

According to the present invention, the receiving means includes: (a) a phase locked loop frequency synthesizer, which outputs a reference signal having a predetermined reference oscillation frequency; Frequency dividing means for dividing the frequency by a frequency ratio, wherein the frequency dividing ratio is variable; voltage-controlled oscillating means for applying the local oscillation signal having a local oscillation frequency corresponding to the input voltage to the frequency dividing means; To the input voltage to change the oscillation frequency, a low-pass filter having a variable time constant, and output a phase comparison signal having a voltage corresponding to the phase difference between the reference signal and the divided output from the dividing means. And a phase comparison means for giving a low-pass filter, wherein the phase comparison signal is a phase-locked signal that operates the voltage control type transmission means so as to reduce the phase difference between the reference signal and the divided output. And-loop frequency synthesizer,
(B) In the low-pass filter, the time constant τ1 during the receiving operation of the receiving means for detecting the received electric field strength by the electric field strength detecting means, and the receiving means for detecting the presence or absence of a broadcasting station by the broadcasting station detecting means. And time constant setting means for setting the time constant to be less than the time constant τ2 during the receiving operation. According to the invention, the receiving means mixes the local oscillation signal from the voltage-controlled oscillating means of the phase locked loop frequency synthesizer with the tuned reception signal to generate an intermediate frequency signal. Hereinafter, the phase locked loop frequency synthesizer is abbreviated as “PLL”. The time constant of the low-pass filter included in the PLL is variable. By changing this time constant, the lock time of the PLL can be changed. The lock time means that the frequency division ratio of the PLL frequency dividing means is changed, and then the local oscillation signal of the local oscillation frequency corresponding to the changed frequency dividing ratio is stably oscillated by the voltage controlled oscillation means. It is time to do it. If the reception tuning frequency is changed by the receiving means, it is necessary to change the local oscillation frequency of the local oscillation signal as well, but during this lock time, it becomes difficult to output an intermediate frequency signal having a stable frequency from the receiving means. . Thus, every time the reception tuning frequency is changed, it is necessary to stop other processing for the lock time each time. Therefore, the processing time of the reception frequency detection processing and the broadcast station detection processing includes the lock time corresponding to the number of times the reception tuning frequency is changed. For example, if the time constant of the low-pass filter is smaller than the original value, the lock time can be shortened, but at the same time, the local oscillation frequency changes with time and becomes unstable. This is because, when the time constant is reduced, the phase comparison signal is not sufficiently smoothed at the time of generation of the input voltage to the voltage-controlled oscillator, so that the level of the input voltage changes with time. As described above, in the electric field strength detection processing in the reception frequency detection processing of the memory initialization processing, the reception electric field strength of the signal on the output line of the intermediate frequency signal is detected. At this time, if the local oscillation frequency of the local oscillation signal is unstable, the frequency of the signal on this output line also becomes unstable.
There is no effect on the electric field strength detection processing. from these things,
In the receiver according to the present invention, the time constant τ1 at that time is determined only during the reception operation of the reception means for detecting the reception electric field intensity by the electric field intensity detection means, and the presence / absence of a broadcasting station is detected by the reception frequency detection means. Is set to be less than the time constant τ2 during the receiving operation of the receiving means. by this,
The lock time of the PLL can be reduced during the reception frequency detection processing as compared with when the remaining processing is performed. In particular, in the reception frequency detection processing, processing is performed for each of a large number of reception tuning frequencies.
The frequency division ratio of L is frequently changed. Since the lock time for each of these changes is reduced, the processing time of the entire reception detection process can be significantly reduced.

Further, according to the present invention, the broadcast station transmits a broadcast wave including a provided signal representing provided information, which is a provided signal other than a sound signal and a video signal of a television broadcast or a sound signal of a radio broadcast program. The broadcast station detecting means includes provided information detecting means for detecting provided information from the received signal, and stores only the reception tuning frequency of the received signal whose provided information is detected by the provided information detecting means in the memory. It is characterized by the following. According to the present invention, in the receiver, an audio signal and a video signal of a television broadcast,
Alternatively, a broadcast wave representing the provided information other than the audio signal of the radio broadcast program is received, and the provided information is demodulated and reproduced. As this provided information, for example, RDS of radio data system
Data, characters and graphics of FM multiplex broadcasting for mobile reception
Traffic information and additional information can be raised. The provided signal representing the provided information is, for example, a subcarrier in the same channel as the audio signal of the radio broadcast program is modulated by the provided signal using a modulation method different from that of the audio signal, and the modulated carrier and the audio signal are multiplexed. Sent. Further, the provided signal may be transmitted independently using the main carrier of a channel not used for transmitting another broadcast wave. For example, when the receiver is a device for receiving only traffic information used in a navigation device, only the broadcasting station frequency of a broadcasting station that transmits traffic information as provision information is stored in the memory in the receiver. Is preferred.
When the receiver of the present invention is such a receiver, the broadcast station detecting means has provided information detecting means for detecting provided information from a received signal. When it is determined that there is a broadcast station having a broadcast station frequency corresponding to the reception tuning frequency, the broadcast station detection means subsequently checks whether or not the provided information can be detected from the received signal of the broadcast station. Only when the provided information is detected, the reception tuning frequency of the received signal is stored in the memory. As a result, even in a receiver that receives only traffic information, the processing time of the memory setting process of the preset memory function can be reduced.

Further, the present invention is characterized in that the predetermined order of the broadcast station detecting means is an order from a large receiving electric field intensity to a small receiving electric field intensity among the receiving tuning frequencies. According to the present invention, the broadcast station detecting means of the receiver sets a receiving tuning frequency to the receiving means in the order from a receiving tuning frequency having a large receiving electric field strength to a small receiving tuning frequency among the receiving tuning frequencies. I do. As a result, the presence / absence of a broadcasting station is sequentially performed from a station having a high reception electric field strength and a good reception state. The above-mentioned memory has a finite capacity, and may not be able to store reception tuning frequencies of all receivable broadcast waves. At this time, the reception tuning frequency of the broadcasting station that has a good reception state and is less affected by noise after demodulation is stored with priority. Therefore, when the capacity of the memory is small, or when there are many broadcast waves in which the level of the received electric field strength is slightly larger than the reference level,
It is possible to give priority to a broadcast wave from a broadcasting station that can reliably receive and demodulate an audio signal.

[0024]

FIG. 1 is a block diagram showing an electric configuration of a receiver 11 according to an embodiment of the present invention.
The receiver 11 has an AM (Amplitude Modula).
tion) A receiver that receives and demodulates a broadcast wave of a radio broadcast and that can simultaneously reproduce a provided signal multiplexed and transmitted with an audio signal of an AM radio broadcast.
The provided information represented by the provided signal includes, for example, character information and traffic information superimposed on FM radio broadcasting. Also, it is conceivable that provided information other than the audio signal is superimposed on the AM radio broadcast.

The receiver 11 is a so-called superheterodyne receiver. Further, the receiver 11 has a so-called preset memory function. With the preset memory function, the reception setting conditions of each circuit for receiving a plurality of receivable broadcast waves are stored in a memory in advance, and when a broadcast wave to be received and demodulated is selected, the reception setting in the memory is set. This is a function of reading conditions and setting each circuit to a state corresponding to the reception of the broadcast wave. The receiver 11 has, for example, a preset switch corresponding to an address indicating a storage position of each reception setting condition in a memory on a one-to-one basis. The user of the receiver 11 can receive and demodulate the broadcast wave of the broadcasting station desired by the user by operating the preset switch only.

The electrical configuration of the receiver 11 will be described below.

The received signal output from the antenna 12 is
The high-frequency tuning / amplifying circuit 13 is provided. A reception tuning frequency corresponding to a broadcast station frequency of a broadcast wave to be received is set in the circuit 13, and the circuit 13 tunes to the reception signal at the reception tuning frequency. The received signal is amplified by the circuit 13 with only the signal component near the broadcast station frequency emphasized, and then mixed by the mixing circuit 15.
Given to. Associated with the mixing circuit 15 is a phase locked loop frequency synthesizer 17 including a local oscillation circuit 16. The phase locked loop frequency synthesizer 17 is hereinafter abbreviated as “PLL 17”. Local oscillation circuit 16 is realized by, for example, a voltage-controlled oscillator, oscillates a local oscillation signal having a local oscillation frequency corresponding to an input voltage described later, and supplies the oscillation signal to mixing circuit 15.

The mixing circuit 15 mixes the local oscillation signal and the received signal to obtain a predetermined intermediate frequency signal. When the received signal is correctly tuned to the broadcast station frequency to be received by the high frequency tuning / amplifying circuit 13, the frequency of the intermediate frequency signal becomes a predetermined intermediate frequency. The intermediate frequency signal thus obtained passes through a filter capable of filtering only a frequency component containing, for example, a desired broadcast wave signal, and is then applied to the intermediate frequency amplifier circuit 20 and amplified. The amplified intermediate frequency signal is provided to the demodulation circuit 19. The demodulation circuit 19 performs AM detection of the intermediate frequency signal, demodulates the received signal, and outputs an audio signal. The audio signal is amplified by the low-frequency amplifier circuit 20 and then output from the speaker 21 as sound.

Further, in the demodulation circuit 19, the intermediate frequency signal is demodulated in a demodulation format according to the modulation format of the provided signal, and the provided signal is output. The modulation scheme of the provided signal is often different from the demodulated component of the audio signal, and is demodulated separately from the audio signal. The provided signal is provided to a central processing unit 29 to be described later, subjected to signal processing, and presented to a user of the receiver 11. For example, when the provided signal represents character information, it is visually displayed using, for example, a liquid crystal display device.

The above-described PLL 17 includes a local oscillation circuit 16.
In addition, the frequency divider 24, the reference oscillation circuit 25, the crystal oscillator 2
6, a phase comparison circuit 27 and a low-pass filter 28 are further included. Further, a central processing unit 29 and a memory 30 are provided in association with the PLL 17. The low-pass filter 28 is abbreviated as “LPF” in the drawing.

The frequency divider 24 is supplied with the same local oscillation signal as the local oscillation signal supplied from the local oscillation circuit 16 to the mixing circuit 15. The frequency divider 24 divides the frequency of the local oscillation signal by the frequency division ratio N, and supplies a divided output to the phase comparison circuit 27. This frequency division ratio N is variable and given from a central processing unit 29 described later. The reference oscillation circuit 25 is a crystal oscillator 2
6 oscillates a reference signal having a predetermined reference frequency based on a signal having a predetermined frequency oscillated by the crystal oscillator 26, and supplies the reference signal to the phase comparison circuit 27.

The phase comparison circuit 27 compares the phases of the reference signal and the frequency-divided output, and outputs a phase comparison signal having a voltage corresponding to the phase difference. The phase comparison signal is smoothed to a DC voltage in the low-pass filter 28, and the smoothed output is provided to the local oscillation circuit 16 as an input voltage. The local oscillation circuit 16 is realized by a voltage-controlled oscillator, and outputs a local oscillation signal having a local oscillation frequency corresponding to the input voltage from the low-pass filter 28. The above-described phase comparison signal has a voltage that causes the local oscillation circuit 16 to operate such that the phase difference between the reference signal and the divided output is reduced.

This input voltage is also supplied to a high-frequency tuning / amplifying circuit 13. The tuning circuit in the circuit 13 includes, for example, a voltage-controlled variable capacitor. By changing the capacity of this capacitor, the detection frequency to be set in the circuit 13 is set as the reception tuning frequency corresponding to the desired broadcast wave.

The memory 30 is a preset memory in the above-described preset memory function. The memory 30 stores reception setting conditions for a plurality of broadcast waves that can be received by the receiver 11. The reception setting condition is, for example, the value of the frequency division ratio N set in the frequency divider 24 when each broadcast wave is to be received and demodulated. Also, a high frequency tuning / amplifying circuit 1
The value of the reception tuning frequency set to 3 and the value of the local oscillation frequency of the local oscillation signal output from the local oscillation circuit may be stored.

The central processing unit 29 controls the high-frequency tuning / amplifying circuit 13 and the PLL based on the contents stored in the memory 30.
17 is controlled. For example, when the preset memory function is operating, the division ratio N of the reception setting condition of the broadcast wave of the broadcasting station desired by the user of the receiver 11 is read from the memory 30 and given to the frequency divider 24 of the PLL 17. by this,
By changing the input voltage from the low-pass filter 28, the reception tuning frequency of the high-frequency amplification / tuning circuit 13 and the PL
The local oscillation frequency of L17 is changed.

In the mixing circuit 15 described above, the mixing circuit 15
In order to set the frequency of the signal output from the PC to the predetermined intermediate frequency, a local oscillation signal having a frequency of the difference between the broadcast station frequency and the intermediate frequency as a local oscillation frequency is required. Therefore, when the broadcast wave to be received is changed and the broadcast station frequency changes, the local oscillation frequency of the local oscillation signal also needs to be changed.

When the broadcast wave desired by the user of the receiver 11 is changed, the central processing unit 29 reads the frequency division ratio N, which is a new broadcast wave reception setting condition, from the memory 30,
This is supplied to the frequency divider 24 of the PLL 17. After changing the frequency division ratio N, the PLL 17 executes the above-described procedure for each of the constituent elements 16,
The processing operations at 24, 27 and 28 are repeated. As a result, the voltage value of the phase comparison signal is sequentially changed so that the phase difference between the signal obtained by dividing the local oscillation signal by the new dividing ratio N and the reference signal becomes 0, and finally the local oscillation circuit 1
6, a value for outputting a local oscillation signal having a local oscillation frequency corresponding to the new frequency division ratio N is obtained. Such an operation enables stable reception of a desired broadcast wave.

In the above-described operation of the PLL 17, the local oscillation circuit 16 outputs a local oscillation signal having a local oscillation frequency corresponding to the frequency division ratio N from the time when the new frequency division ratio N is given from the central processing unit 29. How long it takes
This is referred to as the lock time of the PLL 17. This lock time is
The smaller the time constant of the low-pass filter 28 is, the shorter the time constant is. The time constant of the low-pass filter 28 is variable, and the time constants τ1, τ2
Is switched to either one. The time constant τ1 is the time constant τ
The value is smaller than 2. The lock time of the PLL 17 when switched to the time constant τ1 is shorter than the lock time of the PLL 17 when switched to the time constant τ2.

The receiver 11 includes an electric field strength detection circuit 31
And an IF counter 32. Electric field strength detection circuit 31
The output signal from the above-described intermediate frequency amplification circuit 18 is supplied to the IF counter 32 and the IF counter 32, respectively. The intermediate frequency amplifying circuit 18 is on the output line of the intermediate frequency signal from the mixing circuit 15 to the demodulation circuit 19, and the output signal is
5 is a signal obtained by amplifying the signal from No. 5 at a predetermined amplification factor. The electric field strength detection circuit 31 and the IF counter 3
2 is used in an initialization processing operation of the memory 30 described later.

The electric field strength detection circuit 31 detects the received electric field strength of the broadcast wave to be received and demodulated based on the output signal from the intermediate frequency amplification circuit 18. For example, the circuit 31 has an analog / digital conversion circuit, converts the output signal from analog to digital, and detects the amplitude of the output signal as the level of the received electric field strength. The detected level of the received electric field strength is provided to the central processing unit 29.

The IF counter 32 counts the frequency of the output signal from the intermediate frequency amplifying circuit 18, and supplies the counting result to the central processing unit 29. The IF counter 32 counts, for example, the wave number of the output signal during a predetermined counting time. The frequency of the output signal is determined based on the wave number.

In order to implement the above-mentioned preset memory function in such a receiver 11, the reception setting conditions of broadcast waves of a plurality of receivable broadcast station frequencies are stored in advance in a memory 30 which is a preset memory. There is a need. The central processing unit 29 can perform an initial setting operation of the memory 30 that automatically stores the reception setting conditions of these receivable broadcast waves in the memory.

The initial setting processing operation of the memory 30 will be described.
This will be described below.

The initial setting operation includes a reception frequency detection process and a broadcast station detection process. The reception frequency detection process
This is the first processing of the initial setting processing operation, in which the reception electric field strength at a plurality of frequencies in the entire predetermined frequency band WF1 is detected, and the channel whose reception electric field strength is equal to or higher than the predetermined level is detected. The broadcast station detection process is a second process of the initial setting operation, in which the channel detected in the reception frequency detection process is received again, and the presence or absence of a broadcast station using the channel for transmission is detected.

First, the reception frequency detection processing will be described in detail below.

FIG. 2 is a graph showing a change over time of a detection frequency to be tuned by the high-frequency tuning / amplifying circuit 13 in the above-described reception frequency detection processing.

With respect to a single detection frequency, the high-frequency tuning / amplifying circuit 13 and the PLL 17
The set detection time WT13 from the setting of the detection frequency to the end of the detection of the reception electric field strength is the set time WT11 of the detection frequency.
And the reception electric field strength detection time WT12. As described above, the set time WT11 is a time for shifting the high-frequency tuning / amplifying circuit 13 and the PLL 17 to a state corresponding to the detection frequency, and includes the lock time of the PLL 17. The detection time WT12 is a time required for the operation of detecting the received electric field intensity in the electric field intensity detection circuit 31, and is, for example, 3 ms.

In the reception frequency detection operation, the reception field strength of the broadcast wave of each broadcast station frequency is detected using the broadcast station frequency of each channel in the above-mentioned frequency band WF1 as a detection frequency. The detection order may be, for example, the frequency band WF
The detection frequency value is sequentially increased by the frequency interval WF2 from the frequency f1 having the smallest frequency value among the frequency f1.

The above-mentioned frequency band WF1 is, for example, A
This is a frequency band of M radio broadcasting, which is a frequency band of 522 kHz to 1629 kHz. In this frequency band WF1, for example, m channels having the same bandwidth are set. A broadcast station frequency, which is the frequency of a carrier of a broadcast wave, is set for each channel. Adjacent 2
The frequency interval WF2 between two broadcast station frequencies is the first to
The same is true for the broadcast station frequency of the mth channel. This frequency interval WF2 is, for example, 9 kHz.

For example, as shown by the broken line 41 in FIG.
The set detection time W from the start time t0 of the reception frequency detection operation
By the time t1 after the elapse of T13, the reception electric field strength of the broadcast station frequency of the frequency f1 is detected. Similarly, at times t2, t3, and t4 after the lapse of the set detection time WT13, respectively.
In, the detection of the broadcast station frequencies of the frequencies f2, f3 and f4 ends. Then, from the time t0, the set detection time WT
Time T after elapse of time 13 times (WT13 · m) of 13
At m, the detection of the received electric field strength at each of the frequencies f1 to fm ends.

When the broadcast station frequency of a certain channel is set as the detection frequency, the central processing unit 29 changes the frequency division ratio N of the frequency divider 24 of the PLL 17 to a frequency division ratio N corresponding to the detected frequency. . When the above-described lock time elapses after the division ratio N of the frequency divider 24 is changed, the local oscillation circuit 1
6, a local oscillation signal having a local oscillation frequency corresponding to the detection frequency is stably output. Similarly, when a predetermined time elapses after the division ratio N is changed, the capacitance value of the voltage-controlled variable capacitor of the high-frequency tuning / amplifying circuit 13 is stabilized, and tuning is performed at the reception tuning frequency corresponding to the detection frequency. State. After the high-frequency tuning / amplifying circuit 13 and the PLL 17 reach a sufficiently stable state, the central processing unit 29 causes the electric field intensity detecting means 31 to detect the received electric field intensity of the channel of the detected frequency. In FIG. 2, the symbol s of the broken line 41 indicates the start timing of the electric field strength detection processing.

The central processing unit 29 compares the level of the received electric field strength detected by the reception frequency detecting operation with a predetermined received electric field strength level E1. The device 29 regards the detection frequency when the reception electric field strength equal to or higher than the reception electric field intensity level E1 is detected as being used for transmitting the broadcast wave, and stores the reception setting condition of the detection frequency in the memory 3.
Store to 0. Only the detection frequency stored in the memory 30 is a processing target of the broadcast station detection processing described later.

FIG. 3 is a diagram showing a memory configuration of the memory 30. In the receiving frequency setting processing operation shown in FIG. 2, for example, it is assumed that only the receiving electric field strengths of frequencies f1, f2, and f4 are equal to or higher than predetermined receiving electric field strength E1. At this time, the reception setting condition of the detection frequency with the high reception electric field strength is stored in the memory area where the address is small and the priority is read out. This allows the memory 30
, The reception setting condition of each frequency of the broadcasting station is sequentially read out, and the reception setting condition of the detection frequency whose reception electric field strength was large at the time of the initial setting processing operation is preferentially read.

In this reception frequency processing operation, the detection frequency at which the reception electric field strength is lower than the predetermined level is regarded as the broadcast station frequency of the channel not used for transmitting the broadcast wave, and is not stored in the memory 30. . At this time, it is considered that the antenna 12 is receiving noise other than broadcast waves as a signal of the frequency. In addition, even when there is a broadcasting station having this detection frequency as the broadcasting station frequency, if the receiving position is in a valley of a mountainous area, the receiving electric field strength of the broadcast wave becomes weak if the receiving condition is poor. At this time, even if the broadcast wave is received and demodulated by the receiver 11, it is considered that the influence of noise and the like is large and the broadcast wave cannot be demodulated normally. Therefore, such a detection frequency is excluded from processing targets of a broadcast station detection process described later. Thereby, the number of detection frequencies to be processed in the broadcast station detection processing can be reduced.

When the above-described reception frequency detection operation is completed for all the channels, subsequently, a second process, that is, a broadcast station detection process is performed. The details of the broadcast station detection processing will be described in detail.

FIG. 4 is a graph showing the change over time of the detection frequency in the broadcast station detection processing. In this broadcast station detection process, of a plurality of detection frequencies to be processed, the presence or absence of a broadcast station having a frequency with a large received electric field strength is preferentially detected. For example, in the broadcast station detection process based on the stored contents of the memory 30 shown in FIG. 3, as indicated by the broken line 42, the frequency of the output signal from the intermediate frequency amplification circuit 18 when the frequencies f2, f4, and f1 are the detection frequencies. Are detected in this order.

In order to detect the presence or absence of a broadcasting station using a certain channel for transmitting broadcast waves, first, based on each reception setting condition, the high frequency tuning / amplifying circuit 13 and the PLL 17 are set and the channel of the detection frequency is again set. Receive the frequency of the output signal on the output line of the intermediate frequency signal at that time.
Detected by the counter 32. Next, the central processing unit 29
It is determined whether or not the frequency of the detected output signal is within a predetermined range. The predetermined range is a range obtained by adding the measurement error of the IF counter 32 to the intermediate frequency. When the frequency of the output signal is within this range, it is determined that there is a broadcasting station that uses the channel of the detected frequency at that time for transmitting broadcast waves, and only the reception setting conditions are left in the memory 30. When the frequency is out of this range, it is determined that there is no broadcasting station using the channel of the detected frequency at that time for transmitting the broadcast wave, and the reception setting condition is deleted from the memory 30. Alternatively, a read disable flag is further added to the memory 30 so that the reception setting condition cannot be read when used for the preset memory function.

For example, when a channel adjacent to the channel of the detection frequency is used for transmitting a broadcast wave, the broadcast wave of the adjacent channel leaks to the channel of the detection frequency, and the level of the received electric field strength increases due to the leakage. There is. At this time, the frequency of the output signal from the amplifier circuit 18 on the output line of the intermediate frequency signal is different from the original intermediate frequency. For example, in a receiver for receiving an AM radio broadcast, when receiving a channel used for transmission of a broadcast wave, the frequency of an output signal is 450 k which is an intermediate frequency.
Hz. When a signal leaking from a channel adjacent to this channel and not used for transmitting broadcast waves is erroneously received, the frequency of the output signal becomes 449 kHz, for example, and does not match the intermediate frequency. Also, when the noise level in the vicinity of the detection frequency is extremely high, the reception electric field strength may be erroneously higher than the predetermined reception electric field strength level, and the frequency of the output signal at this time is also the intermediate frequency. different.

As described above, by checking the actual frequency of the signal on the output line of the intermediate frequency signal, the erroneous detection of a broadcast wave of an adjacent channel or the like by mistake causes the reception electric field strength to become a predetermined level. The reception setting condition can be removed from the memory 30 of the preset memory function.

In the processing operation shown in FIG. 4, only when the frequency f2 is set as the detection frequency, the frequency of the output signal from the amplifier circuit 18 matches the intermediate frequency, and the broadcast station uses the detected frequency as the broadcast station frequency. Is determined. Folded line 4 in FIG.
In FIG. 2, “C” indicates the start timing of the frequency counting operation. At this time, an operation of detecting the presence or absence of the provided information is performed. When the frequencies f1 and f4 are set as the detection frequencies, the frequency of the output signal of the amplifier circuit 18 does not match the intermediate frequency, and it is determined that there is no broadcast station having the detected frequency as the broadcast station frequency.

When the receiver 11 is a receiver that receives only the provided information described above, the central processing unit 29 further determines whether or not the provided information is included in the broadcast wave. The receiver 11 detects only a broadcasting station whose broadcast wave frequency is the detection frequency of the broadcast wave including the modulation component modulated by the provided signal representing the provided information. At the folding line 42 in FIG.
“D” indicates the start timing of the operation of detecting the provided information.
To detect the provided information, for example, after the received signal is demodulated by the demodulation circuit 19, the demodulated output is sent to the central processing unit 29.
, It is determined whether or not desired provided information can be obtained by performing signal processing.

For example, in a radio data system, RDS data, which is information to be transmitted, is represented by a digital signal. In order to generate an RDS signal representing the RDS data, first, the RDS data itself is subjected to differential encoding processing and converted, and then the converted signal is converted to 1.187.
A 5-kHz clock signal is converted to two-phase PSK (Phase ShiftKey).
ing) Modulate by the modulation method. Subsequently, the subcarrier having the frequency of 76 kHz is converted to the DSB by the modulated clock signal.
(Double Side Band) modulation to obtain an RDS signal. The RDS signal is multiplexed with an audio signal of FM radio broadcast and transmitted.

In the mobile reception FM multiplex broadcasting, for example, digital data representing character / graphic / traffic information including text news and additional information including the name of the broadcasting station being received is transmission data to be transmitted. A data signal representing the transmission data is generated by modulating a subcarrier having a frequency of 76 kHz by the L-MSK modulation method using the transmission data. The data signal is transmitted after being multiplexed with the audio signal of the FM radio broadcast.

As described above, in the radio data system and the mobile reception FM multiplex broadcast, the RDS signal or the data signal is multiplexed on the audio signal of the radio broadcast program. The sub-carrier frequency and modulation scheme of the RDS signal and the data signal and the original data format are different from the carrier frequency, modulation scheme and data format of the original signal of the audio signal of the broadcast program. Therefore, when the output signal from the intermediate frequency amplifier circuit 18 is demodulated based on these different signal formats, it is possible to obtain RDS data and transmission data only when the original broadcast wave contains the RDS signal and the data signal. Can be. As described above, by determining whether or not the RDS data and the transmission data can be reproduced, the detection frequency set in the high-frequency tuning / amplifying circuit 13 and the PLL 17 allows the broadcast information of the broadcasting station that multiplexes and transmits the information to transmit. It can be determined whether or not the wave frequency is used.

The set detection time WT18 of the broadcast station detection processing operation relating to a single detection frequency is the sum of the set time WT15 of the detection frequency, the detection time WT16 of the broadcast station, and the detection time WT17 of the provided information. This set detection time WT18
Is 25 ms, for example. Setting time W of detection frequency
T15 is the same as the reception frequency detection processing,
This is a time for shifting the amplifier circuit 13 and the PLL 17 to a state corresponding to the detection frequency. The broadcast station detection time WT16 is a time for detecting the frequency of the output signal and comparing it with the intermediate frequency, including the counting time of the wave number of the output signal in the IF counter 32 described above. The provided information detection time WT17 is a time for the central processing unit 29 to demodulate and reproduce the provided information and detect the presence or absence of the provided information.

FIG. 5 is a flowchart for explaining the reception frequency detecting operation in the initial setting operation of the memory 30 of the receiver 11.

For example, the central processing unit 29 has the receiver 11
When the user instructs to execute the initial setting processing operation,
The process proceeds from step a1 to step a2. In step a2, the detection frequency at which the electric field intensity detection circuit 31 should detect the received electric field intensity is set to the lowest frequency. The lowest frequency is a frequency having the smallest value among broadcast station frequencies of channels set in a frequency band in which all broadcast wave frequencies of the type receivable by the receiver 11 exist. To set the detection frequency to the lowest frequency, the frequency division ratio N of the frequency divider 24 of the PLL 17 is changed to a value corresponding to the lowest frequency. When the lowest frequency is set, the process proceeds from step a2 to step a3.

In step a3, the low-pass filter 28
Is changed from the preset time constant τ2 to the time constant τ1 to reduce the time constant. When the time constant is changed, the process proceeds from step a3 to step a4, where the high-frequency tuning / amplifying circuit 13 receives and demodulates the broadcast wave having the detected frequency.
Of the reception tuning frequency and the local oscillation frequency of the PLL 17 are started. When the change process is started, the process proceeds from step a4 to step a5, and it is determined whether the set time WT11 of the single detection frequency has elapsed from the start of the change process.

As described above, the set time WT11 is equal to P
The lock time includes the lock time of the LL 17 and substantially coincides with the lock time. The lock time differs depending on the time constant of the low-pass filter 28. The time constant of the low-pass filter 28 is set to the time constant τ1 only during the reception frequency detection operation. This time constant τ1 is smaller than the time constant τ2 of the remaining operation other than the reception frequency detection operation. Therefore, the lock time of the PLL 17 in the reception frequency detection process is shorter than the lock time W12 of the PLL 17 during the remaining operation.

When it is determined that the set time WT11 has elapsed, the process proceeds from step a5 to step a6. Set time W
When T11 has elapsed, the mixing circuit 15 outputs a signal whose frequency has been converted in accordance with the desired detection frequency.
In step a6, the output signal of the intermediate frequency amplifying circuit 18 is supplied to the electric field strength detection circuit 31, and the received electric field strength is detected. When the detection of the reception electric field strength is completed, the process proceeds from step a6 to step a7.

At step a7, it is determined whether or not the detected level of the received electric field strength is higher than a predetermined received electric field strength level E1. If so, the process proceeds from step a7 to step a8. In step a8,
This detection frequency is applied to the high-frequency tuning / amplifying circuit 13 and the PL
The reception setting condition to be set in L17 is stored in the memory 30. When the reception setting condition is stored in the memory, the process proceeds from step a8 to step a9. Also, when the level of the received electric field strength detected in step a7 is equal to or lower than the predetermined received electric field strength level E1, step a7 is performed.
From step a9.

At step a9, it is determined whether or not the reception electric field strength has been detected over the entire predetermined frequency band. That is, it is determined whether or not the reception electric field strength at the time of receiving the channel of the maximum broadcast station frequency among the channels within this frequency band has been detected. If the frequency is not detected, the process proceeds from step a9 to step a10, where the frequency division ratio N corresponding to the next detection frequency whose frequency is higher by one channel than the detection frequency currently set in the high frequency tuning / amplifying circuit 13 and the PLL 17 is set. This is applied to the frequency divider 24 of the PLL 17 and the operation returns to step a4. This operation is performed with respect to the broadcast station frequencies of all the channels within the predetermined frequency band.

If it is determined in step a9 that the detection of the received electric field strength has been completed for all the channels in the band, the process proceeds from step a9 to step a10, and the processing operation of the flowchart ends.

FIG. 6 is a flowchart for explaining the processing operation of the broadcast station detection processing in the memory initialization processing operation of the receiver 11.

When the reception frequency detecting process shown in FIG. 5 is completed, the process proceeds from step b1 to step b2. Step b
In 2, the detection frequency to be set in the high-frequency tuning / amplifying circuit 13 and the PLL 17 is set to the frequency at which the reception electric field strength at the time of reception is the highest among the frequencies in which the reception setting conditions are stored in the memory 30, and the frequency is divided. The frequency division ratio N corresponding to the frequency is given to the detector 24. When the setting of the frequency is completed, the process proceeds from step b2 to step b3.

At step b3, the time constant of the low-pass filter 28 of the PLL 17 is returned from the above-mentioned time constant τ2 to the time constant τ1. Thus, the time constant of the low-pass filter 28 becomes larger than the time constant τ2 in the reception frequency detection processing. When the time constant is increased in this manner, the PLL
Although the lock time of the signal 17 becomes long, it is possible to prevent the input voltage supplied to the high-frequency tuning / amplifying circuit 13 and the local oscillation circuit 16 from frequently changing. When the change of the time constant is completed, step b3 to step b4
Proceed to.

In step b4, as in step a4 in the flowchart of FIG. 6, the output operation of the detection frequency is started. After a lapse of the set time WT15 in which the behaviors of the high-frequency tuning / amplifying circuit 13 and the PLL 17 are stabilized, the IF counter 32 starts counting the frequency of the output signal of the intermediate frequency amplifying circuit 18 continuously. When the output operation is started, the process proceeds from step b4 to step b5.

At step b5, it is determined whether or not the time which is the sum of the above-described detection frequency setting time W15 and the broadcast station detection time WT16 shown in FIG. 5 has elapsed. If the time has not elapsed, the process returns to step b5, and this determination is repeated until the time elapses. When the time elapses, the process proceeds from step b5 to step b6. At this time, the counting of the output signal of the intermediate frequency amplification circuit 18 is completed from the IF counter 32, and the data of the frequency is given to the central processing unit 29. In step b6, the central processing unit 29 determines whether or not there is a broadcast station whose detection frequency is the broadcast station frequency based on the output from the IF counter 32. When it is determined that a broadcast station exists, the process proceeds from step b6 to step b7.

At step b7, it is determined whether or not the receiver 11 is a receiver for receiving a broadcast wave from an information providing broadcast station. If so, the process proceeds from step b7 to step b8, and based on the demodulated output from the demodulation circuit 19, the central processing unit 29 further demodulates and reproduces the provided signal to detect the provided information. When the provided information is detected, the process proceeds from step b8 to step b9, and it is determined whether the provided information has been obtained. When the provided information cannot be obtained, it is determined that the broadcast signal having the detected frequency as the broadcast station frequency does not superimpose the provided signal on the broadcast wave, and the process proceeds from step b9 to step b10. When it is determined in step b6 that there is no broadcast station whose detection frequency is the broadcast station frequency, the process proceeds from step b6 to step b10.

In step b10, a memory storing the reception setting condition of the detection frequency determined to be a frequency other than the broadcasting station frequency and the detection frequency determined to be the broadcast wave frequency of the broadcasting station other than the information providing broadcasting station. Delete data in the area. As a result, the setting condition of the detection frequency is deleted from the memory, and the detection frequency when the preset memory function is operating is not set. When data is deleted, steps b10 to b
Proceed to 11. Further, in step b7 described above,
When the receiver 11 is a receiver that does not target the information providing broadcast station, or a receiver that receives both the information providing broadcast station and the remaining broadcast stations, the process proceeds directly from step b7 to step b11. At this time, in the processing operation of step b10 described above, of the detection frequency setting conditions in the memory, only the data of the detection frequency setting condition different from the broadcast station frequency is deleted.

At step b11, it is determined whether or not the broadcast station detection processing has been performed for all the detection frequencies stored in the memory 30. If not, the process proceeds from step b11 to step b12, in which the next detection frequency having a higher reception electric field strength than the reception electric field strength of the detection frequency currently set in the high frequency tuning / amplifying circuit 13 and the PLL 17 is set to the high frequency tuning / amplification. Circuit 13 and PLL1
7 and the process returns to step b4 to perform the broadcast station detection processing for the next detection frequency.

When the determination process for all the detection frequencies in the memory 30 is completed, the memory 30 stores the reception setting condition of the detection frequency, which is the broadcast station frequency of any broadcast station, or the broadcast station of the information providing broadcast station. Only the reception setting condition of the detection frequency which is the frequency is stored. In such a state, the process proceeds from step b11 to step b13,
The processing operation of the flowchart ends.

By performing the above processing, only the setting conditions of the detection frequency which is the broadcasting station frequency of any broadcasting station or the setting conditions of the detection frequency which is the broadcasting station frequency of the information providing broadcasting station are stored in the memory 30. Is stored. Thereafter, when the preset memory function is performed, if the setting conditions stored in the memory 30 are used, only the detection frequency at which the broadcast wave of the broadcasting station or the information providing broadcasting station can be reliably received is determined by the PLL 17 and the high frequency tuning / amplifying circuit 13. Will be set to Through the processing operations described above, the initialization process of the memory 30 of the receiver 11 is performed.

The operation of initializing the memory 30 in the receiver 11 of the present embodiment described above was compared with the operation of initializing the memory in the conventional receiver. The results of the comparison are shown below. It is assumed that the receiver 11 of the present embodiment and the receiver of the related art are both receivers for receiving AM radio broadcasting. These receivers have the same installation positions, and can receive broadcast waves from 10 broadcast stations and demodulate them well.

First, the processing time when the memory initialization processing operation is performed in the conventional receiver is calculated.
In the conventional receiver, first, the presence or absence of a broadcasting station is detected for each channel over the entire frequency band in which the broadcasting station frequency of AM radio broadcasting exists. The processing time W21 of this broadcast station detection operation is calculated to be 3690 ms from the following equation.

[0086]

(Equation 1)

When the broadcast station detection processing operation is completed, the reception electric field strength of each receivable broadcast station is detected. The processing time W22 of this electric field strength detection operation is calculated to be 30 ms from the following equation.

W22 = 10 [stations] × 3 [msec] = 30 [msec] (2) The processing time W23 of the initial setting processing operation is the sum of these processing times W21 and W22. From 3720m
It was calculated to be seconds.

W23 = W21 + W22 = 3690 [msec] +30 [msec] = 3720 [msec] (3) Subsequently, the processing time in the receiver 11 of the present embodiment was calculated. The receiver 11 of the present embodiment first performs the above-described reception frequency detection processing based on the detected reception electric field strength. It is assumed that the above-described detection processing time W13 per channel is 3 ms. At this time, the processing time W24 of the reception frequency detection processing was calculated to be 369 msec from the following equation.

[0090]

(Equation 2)

Subsequently, the above-described broadcast station detection processing is performed on the ten receivable broadcast stations. It is assumed that the above-described detection processing time W18 per channel is 30 ms. At this time, the processing time W25 of the broadcast station detection processing was calculated to be 300 msec from the following equation.

W25 = 10 [stations] × 30 [msec] = 300 [msec] (5) The processing time W26 of the entire initial setting processing operation is the sum of these processing times W24 and W25. From equation 669
It was calculated to be m seconds.

W26 = W24 + W25 = 369 [msec] +300 [msec] = 669 [msec] (6) As described above, the receiver according to the related art and the receiver 1 according to the present embodiment are as described above.
1 and the processing time of the initial setting processing operation is compared with the processing time W in the receiver 11 of the present embodiment.
26 is 1/5 of the processing time in the prior art receiver
It turns out that it is less than. As described above, in the receiver 11 of the present embodiment, the processing time of the initial setting process of the memory 30 can be reduced as compared with the receiver of the related art.

The above-described receiver 11 of the present embodiment has the AM
The receiver is assumed to receive radio broadcasts. The operation of initializing the memory of the preset memory function described above may be performed by a receiver that receives FM radio broadcasts and television broadcasts in addition to the AM radio broadcast receivers. In addition, VI attached to the navigation device
It may be performed in the CS receiver. In addition, any receiver having a preset memory function may be used.

[0095]

As described above, according to the present invention, the receiver has a preset memory function, and the reception tuning frequency of the receivable broadcasting station is automatically set in the memory in advance. When this memory initialization process is performed, the receiver first detects the reception field strength of each channel, and then determines whether or not there is a broadcasting station that uses the channel only for the channel whose level is equal to or higher than a predetermined level. Is detected.
This makes it possible to reduce the number of times of processing of the broadcast station detection processing that takes a longer processing time than the electric field strength detection processing in the processing for a single channel. Therefore, it is possible to reduce the processing time of the entire initial setting process for the memory.

While the memory initial setting process is performed,
The receiver cannot be used for receiving and demodulating broadcast waves,
Although it is not possible to listen to or watch a broadcast program, the receiver of the present invention reduces the processing time,
The time during which listening or viewing cannot be performed can be reduced. Therefore, discomfort felt by the user of the receiver can be reduced. Further, the processing of the present receiver can be performed without making a significant change to the circuit configuration of the current receiver, so that the processing is easy.

Further, according to the present invention, when the receiver is a superheterodyne type device, only by examining the frequency of the signal on the output line of the intermediate frequency signal, the broadcast station corresponding to the reception tuning frequency at that time is checked. Presence or absence can be detected. Since the presence or absence of the frequency can be easily detected by the frequency counter, the implementation is easy.

Further, according to the present invention, the time constant of the low-pass filter of the PLL of the receiving means is variable. By changing the time constant, the lock time of the PLL can be changed, and the processing time of the reception frequency detection processing can be further reduced. As a result, the processing time of the memory setting process, which is shorter than that of the device of the related art, can be further reduced.

Further, according to the present invention, the receiver comprises:
When the apparatus receives and uses only the provided information other than the audio signal and the video signal of the television broadcast or the audio signal of the radio broadcast program, only the reception tuning frequency of the broadcasting station transmitting the provided information is stored in the memory. Then, the preset memory function is performed. Thus, even in a receiver that receives only traffic information, for example, the memory setting process of the preset memory function can be automatically performed by the receiver itself, and the processing time can be reduced.

Further, according to the present invention, the broadcasting station detecting means of the receiver sends the receiving means in order from the receiving tuning frequency having a large receiving electric field strength to the receiving tuning frequency having a small receiving frequency among the receiving tuning frequencies. Set the reception tuning frequency. Thus, for example, when the capacity of the memory is small, a broadcasting station that can receive data reliably and has good demodulated audio and video conditions is stored in the memory with priority.
Therefore, when the preset memory function is performed, a broadcast station in which the state of the demodulated audio and video is poor even if receivable, is omitted, so that the broadcast can be reliably heard and viewed in a good state. .

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating an electrical configuration of a receiver 11 according to an embodiment of the present invention.

FIG. 2 is a graph showing a change over time of a detection frequency in a reception frequency detection operation of an initialization processing operation of a memory 30 of the receiver 11;

FIG. 3 is a diagram specifically showing memory contents of a memory 30.

FIG. 4 is a graph showing a change over time of a detection frequency in a broadcast station detection process in an initialization process of the memory 30 of the receiver 11;

FIG. 5 is a flowchart for describing a detailed processing operation of a reception frequency detection process of an initialization process operation of the memory 30 of the receiver 11;

FIG. 6 is a flowchart for explaining a detailed processing operation of a broadcast station detection process of an initial setting process operation of the memory 30 of the receiver 11;

FIG. 7 is a graph showing a change over time of a detection frequency in a memory initial setting processing operation of the receiver of the related art.

[Explanation of symbols]

 Reference Signs List 11 receiver 12 antenna 13 high-frequency tuning / amplifying circuit 15 mixing circuit 16 local oscillation circuit 17 phase locked loop frequency synthesizer 24 frequency divider 25 reference oscillation circuit 26 crystal oscillator 27 phase comparison circuit 28 low-pass filter 29 central processing unit 30 memory 31 electric field strength detection circuit 32 IF counter

Claims (5)

[Claims] 1. Receiving means for tuned at a plurality of reception tuning frequencies in the entire frequency band in which a broadcasting station frequency exists and outputting a received signal, a memory for storing the reception tuning frequency of the receiving means, and receiving means And an electric field intensity detecting means for detecting a reception electric field intensity for each reception tuning frequency, and a reception electric field among reception reception frequencies of all received signals in response to an output of the electric field intensity detection means. A receiving frequency detecting means for detecting a receiving tuning frequency having a level of intensity equal to or higher than a predetermined level; and a receiving means for responding to the output of the receiving means and the receiving frequency detecting means, and presetting each receiving tuning frequency detected by the receiving frequency detecting means. Tuned by the receiving means in order and received, detecting the presence or absence of a broadcast station of the received tuning frequency from each received signal,
A broadcast station detecting means for storing only a reception tuning frequency in which a broadcast station exists in a memory. 2. The receiving means is of a superheterodyne type, the broadcasting station detecting means is a frequency counter for detecting a frequency of a signal on an output line of an intermediate frequency signal of the receiving means, and a frequency detected by the frequency counter. 2. The receiver according to claim 1, further comprising: determination means for determining that a broadcasting station is present only when is a predetermined intermediate frequency. 3. The receiving means comprises: (a) a phase locked loop frequency synthesizer, which outputs a reference signal having a predetermined reference oscillation frequency; Frequency-dividing means for dividing the frequency and the frequency-dividing ratio are variable; voltage-controlled oscillating means for applying the local oscillation signal having a local oscillation frequency corresponding to the input voltage to the frequency-dividing means; A low-pass filter having a variable time constant, a phase comparison signal having a voltage corresponding to a phase difference between a reference signal and a frequency-divided output from the frequency divider, and a low-pass filter. And a phase comparison signal for operating the voltage control type transmission means so as to reduce a phase difference between the reference signal and the divided output.
(B) in the low-pass filter, a time constant τ1 during a reception operation of the reception means for detecting a reception electric field intensity by the electric field intensity detection means, and presence / absence of a broadcast station by the broadcast station detection means. 3. The receiver according to claim 2, further comprising: a time constant setting unit that sets the time constant to less than a time constant τ2 during a receiving operation of the receiving unit for detecting the time constant. 4. The broadcast station for transmitting a broadcast wave including an audio signal and a video signal of a television broadcast or an audio signal of a radio broadcast program other than an audio signal of an audio signal of a radio broadcast program and including the provided signal representing the provided information. The broadcast station detecting means includes provided information detecting means for detecting provided information from the received signal, and stores only the reception tuning frequency of the received signal for which the provided information is detected by the provided information detecting means in the memory. The receiver according to claim 1, wherein 5. The receiver according to claim 1, wherein the predetermined order of the broadcast station detecting means is an order from a large reception electric field strength to a small reception electric field strength among the respective reception tuning frequencies. .