JPH03212029A - Automatic follow-up method - Google Patents

Abstract

PURPOSE:To update an AF station without a sense of incongruity even when a reception state is deteriorated rapidly by monitoring a signal level of a current reception station through the use of a signal meter and receiving a same program broadcast station whose signal level is maximum. CONSTITUTION:A signal meter 10 detects the level of a reception state of a current reception station by monitoring the intensity of an intermediate frequency signal outputted from an intermediate frequency amplifier 3, e.g. an electric field strength. When the output of the signal meter 10 reaches a 1st level or below, the detection of the same program broadcast station whose signal level is maximum is started and when the output reaches a 2nd level or below during the detection, the detection is interrupted and the same program broadcast station whose signal level is maximum among stations detected before interruption is made receptible. Thus, even when the reception level is rapidly deteriorated, the reception station is selected to a station with excellent reception state instantly.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to an automatic tracking method for shifting to the same program broadcasting station with good reception using a digital data multiplex system. The present invention relates to an automatic tracking method that can quickly shift to the same program broadcasting station with good reception even when the level of the broadcasting station suddenly deteriorates.

Prior Art In car radios, tuning is difficult because it is usually operated by the driver, and it is necessary to reselect the station each time the car travels a long distance and leaves the receiving station's service area. There has been a demand for more advanced functionality. This demand was particularly strong in Europe, where radio broadcasting services mainly consist of FM broadcasting, which has a relatively narrow service area, and where a high proportion of broadcasts are received on car radios. A digital data transmission system standardized by the European Broadcasting Union to meet this requirement is RDS (Radio Data System).

RDS is a method for transmitting various types of digital data (data that can be used for automatically selecting the best reception station, classifying traffic information, displaying the name of the broadcasting station, etc.) on FM radio broadcasts.
By using the code and the PI code, it is possible to perform eye movement tracking that successively receives broadcast stations with the same broadcast content that have good reception conditions.

The AF code is called an alternative frequency code and corresponds to the frequency code of a broadcasting station (AF station) that broadcasts the same program in the same or adjacent reception area. All broadcast station frequencies can be found. Further, the PI code is called a program identification code, and is a unique code given to the same broadcast program (program), and even if the broadcast station is different, if the program is the same, it has a common PI code.

Conventionally, when automatic tracking of the same broadcasting station is performed using, for example, a receiver with a single tuner configuration, the signal strength (for example, electric field strength) of the broadcasting station currently being received is determined based on the above-mentioned AF code, and the -search field strength. It compares strong AF stations and automatically receives a new AF station with a stronger electric field of 91 degrees than the receiving station.

<Problems to be Solved by the Invention> However, the conventional automatic tracking method has a problem with the current receiving station ratio @;!
When finding the strongest station among the target AF' stations,
'Since the selection is made from among all the stations in J-strike, if a car enters a place where it is easily affected by the Tanimadera multipath shadow 41 of a building and the reception condition suddenly deteriorates, the update of the AF station will be delayed. Therefore, there are problems such as abnormal noise being output from the speaker and causing discomfort to the user.

From the foregoing, it is an object of the present invention to provide an automatic tracking method that allows updating of AF stations without causing discomfort even when reception conditions suddenly deteriorate.

<Means for Solving the Problems> In the present invention, the above problem is solved by a means for monitoring the signal level of the current receiving station, and when the output of the monitoring means falls below a first level, the same program broadcasting at the maximum signal level is performed. If station detection is started and the output of the monitoring means becomes equal to or lower than a second level during the detection, the detection is interrupted and the same program broadcasting station whose signal level is the highest among the stations detected before the interruption is detected. This is achieved by a control means that enables reception of the information.

<Function> Monitors the No. 1g level of the receiving station (when the signal frequency of the receiving station becomes below the first level by the visual means, the detection of the same program broadcasting station with the highest signal level is started, and during the detection When the output of the monitoring means becomes equal to or lower than the second level, the detection is interrupted, and the same program broadcasting station with the highest signal level can be received at the instep of the station detected before the interruption.

<Embodiment> FIG. 1 is a block diagram of the main parts of a radio data system receiver that implements the automatic tracking method according to the present invention.

1 is a PLL circuit, which outputs a predetermined voltage signal to the front end 2 according to the station to be received.

The front end 2 connects an antenna (AN) based on the voltage signal.
It receives a broadcast station input from T) and generates a predetermined intermediate frequency signal (IF). 3 is an intermediate frequency amplification circuit;
Amplifying the intermediate frequency signal.

Reference numeral 4 denotes an optical F detector, which transversely converts the intermediate frequency signal converted by the front end 2 and amplified by the intermediate frequency amplification circuit. 5 is a stereo fourth I modulation circuit, which demodulates the detection output of the IFI waver 4 into a stereo signal. 6 is an amplifier;
Amplify stereo signals.

A speaker 7 is driven by the amplifier 6 and outputs an audio signal corresponding to the stereo signal.

8 is an RDS decoder, which demodulates the AF code etc. sent at a predetermined transmission timing. Reference numeral 9 denotes an error correction circuit, which detects errors in RDS data such as AF codes demodulated by the RDS decoder 8 while synchronizing each group, and corrects the errors.

10 is a signal meter, which measures the signal strength (for example, electric field strength) of the intermediate frequency signal output from the intermediate frequency amplifier 3.
It can detect the level of reception status of the receiving station by monitoring the trap.

11 is a control unit that controls the overall operation of the radio data system receiver, which compares the signal strength of the receiving station and the signal frequency of the AF station based on the detection level of the signal meter 10, and selects the AF with the strongest signal strength. It has comparison means 12 for detecting stations. In addition, the control unit 11 obtains the AF code number of the same program being broadcast, which is sent M-folded with the received broadcast signal, via the RDS decoder 8 and the error correction circuit 9, and controls the frequency based on the AF code. # Output the double number to the PLL circuit 1 and perform own T@ tracking.

Next, the operation of the standalone radio receiver of the present invention during automatic tracking will be explained according to the processing flowchart shown in FIG. 2. When an arbitrary broadcasting station is selected (step 101), the control unit 11 uses 8. Check whether the RDS code of the AF code and PR code is superimposed on the received broadcast signal via the error correction circuit 9 (step 102).
). If the RDS code is N-folded, the control unit 11 reads the RDS code and monitors the signal 1 degree of the received signal using the 7-signal meter IO (step 103).

The input level of the receiving station is the first threshold level E1
When the detection signal level is below (step 104), the signal meter IO is referred to and the comparison means 12 is started to compare the signal strong motion of the AF station.Step 105)
Start detecting stations (MAX stations) (step 1u6)
. In that case, if the AF'J strike station is as shown in Figure 3, first, 87.9 MHz and 88.0 MHz
Compare the signal strengths of the AF stations. Further, the control unit 11 determines whether the level of the station currently being received is a second threshold level E2 (E2<El
) or less (step 107), and if it is less than E2, that is, the signal level of the station currently receiving is E1.
and E2, it is confirmed that all AF stations have been checked (step 108), and if not, the next AF station, 88.1 MHz, is detected (step 109). After going through steps 103 and 104, in step 105, a comparison is made with the AF station whose signal strength was found to be higher in the previous comparison. The above MAX station detection operation is continued while the antenna input level of the station currently receiving is between E and E2 until all AP' stations have been checked. When all the AF stations have been checked in step 108, the station with the highest signal strength among all the AF stations is detected, so the control section 11 uses the comparison means 12 to compare it with the station currently being received. Step 1 Comparing the signal strong motion of MAX station
10) If the No. 3 strength of the MAX station is strong, the detected MA
Move the receiving station to the XAF station (Step 111), and determine whether the set station and the receiving station are the same PI (
Step 112), if it is the same PI, the PLL circuit 1 temporarily suspends the broadcast currently being received and performs down-seek or up-seek intermittently to tune to the MAX station (step 114). If it is not the same PI, it is determined that it is a station in another network, and the receiving station is not changed (step 113), and the station determined to be the MAX station such as AF IJ Last is deleted (step 114). ), if the reception level at which the MAX station is detected again is the threshold level & below 11C, the broadcast itself is usually unbearable to listen to. Therefore, in step 107, when the reception condition becomes lower than E2, that is, when the reception condition suddenly deteriorates while detecting the MAXAF station, the control unit 11
Interrupt station 5111 and compare the AF station with the highest signal level among the stations detected before interruption and the current receiving station (
Step 115), if the signal strong motion of the MAX station is strong, M
Along with moving the receiving station to the AXAF station (step 116)
, determine whether it is the same PI (step 117), 1
If it is lffl-PI, the processing from step 114 onwards is performed. If it is not the same-PI, MAXA is selected from the AF list.
Station F is deleted (step 118), and it is determined whether the signal strength of the station currently being received is below E2 (step 119).

If it is in the state of E2 or lower, detect an AF station that has not been checked yet (step 120), compare the level with the receiving station (step 121), and determine whether it is the same PI (step 122). .

If it is the same PI, the process from step 114 is performed, and if it is not the same PI, the process from step 119 is performed to delete the AF station from AF IJ (step 123). If no receivable station is detected in step 115, the process from step 120 is performed, and if it is detected in step 119 that the reception state has recovered, the process from step 103 is performed again. Search for receivable stations.

Note that the automatic tracking operation described above is performed by interrupting broadcasting during dust reception for a length of time that does not cause discomfort.

<Effects of the Invention> As described above, according to the present invention, when the signal strength of the receiving station becomes equal to or lower than the first level by the monitoring means that monitors the signal level of the receiving station, the calibration of the same program broadcasting station with the highest signal level is performed. and when the output of the monitoring means falls below a second level during the detection, the detection is interrupted and the same program broadcasting station with the highest signal level among the stations detected before the interruption is received. This makes it possible to instantly switch the receiving station to a station with better reception even when the reception level has deteriorated significantly, preventing abnormal noise from being generated from the speaker and causing discomfort to the user. can.

[Brief explanation of drawings]

FIG. 1 is a block diagram of the main parts of a radio data system receiver that implements the automatic tracking method according to the present invention, FIG. 2 is a flowchart of the process of the present invention, and FIG. 3 is a diagram showing an example of an AF frequency list. . l...PLL, 2...FM front end, 8...
RDS decoder, 9...Error correction circuit, 10...
Signal meter, ll...controller, 12...comparison means.

Claims (1)

[Claims] A broadcasting station that is broadcasting the same program as the program currently being received is identified based on digital data of a digital data multiplexing system, and a broadcasting station that is currently broadcasting the same program as the program currently being received is identified. In an automatic tracking method that compares signal strengths of each other and shifts to the same program broadcasting station whose signal strength is higher than that of the current receiving station, a monitoring means for monitoring the signal level of the currently receiving station is provided, and the output of the monitoring means is the first one. When the signal level falls below the second level, the detection of the same program broadcasting station with the highest signal level is started, and when the output of the monitoring means becomes below the second level during the detection, the detection is interrupted, and the detection is stopped before the interruption. An automatic tracking method characterized by making it possible to receive the same program broadcasting station with the highest signal level among the stations.