JP2005130225A - Receiver - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a receiver capable of detecting the proper number of broadcasting stations. <P>SOLUTION: A control part 30 acquires broadcasting station information showing the number of receivable broadcasting stations, from a navigation device 80 and refers to a table in a memory 32 on the basis of the broadcasting station information to set a detection level corresponding to the number of broadcasting stations. When a level of an S meter signal output from an S meter 12 gets equal to or higher than this detection level, the control part 30 detects a broadcasting station on the assumption that a broadcast signal exists at the reception frequency. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a receiver that detects a broadcast wave having a high electric field strength by sweeping a frequency.

Conventionally, a receiver that varies the search level of a receiver based on position information is known (see, for example, Patent Document 1). In this receiver, an optimum search level in terms of geography is set by referring to a geography / gain table based on position information output from the navigation system. This makes it possible to set an optimum search level depending on the distance from the broadcast station.
JP-A-4-326627 (page 3-4, FIG. 1-2)

  By the way, in the receiver disclosed in Patent Document 1 described above, it is possible to set the optimum search level depending on the distance from the broadcast station by setting the search level based on the position information. Even if the distance from the receiver is the same, depending on whether the receiver is installed in a metropolitan area where there are many broadcasting stations or in a local area where there are only a few broadcasting stations, the same search level is supported. There has been a problem that the number of broadcast stations that can be detected varies greatly. For example, in a metropolitan area where there are many broadcasting stations, the transmission output of each broadcasting station is often large, so unless the detection level is increased, many broadcasting stations will be detected unnecessarily. . Conversely, in regions where the number of broadcasting stations is small, not only the number of broadcasting stations is small, but also the transmission output of the broadcasting stations is often small, so it is impossible to detect most broadcasting stations unless the detection level is lowered. Become. In addition, since multipath and adjacent interference levels are strongly affected by the received electric field strength, optimal settings cannot be realized if the detection levels are common to each region.

  The present invention has been created in view of such a point, and an object thereof is to provide a receiver capable of detecting an appropriate number of broadcasting stations.

  In order to solve the above-described problem, a receiver according to the present invention detects broadcast signals based on broadcast station information acquisition means for acquiring broadcast station information indicating the number of receivable broadcast stations and broadcast station information. Detection level setting means for setting a detection level, broadcast station detection means for detecting a broadcast signal having a signal level equal to or higher than the detection level, and broadcast signal reception means for receiving a broadcast signal detected by the broadcast station detection means ing. Setting a certain detection level is not preferable because many broadcast stations are detected in the vicinity of a large city with many broadcast stations, but almost no broadcast stations are detected in a region with few broadcast stations. However, by setting the detection level according to the number of receivable broadcast stations, such a situation can be avoided and an appropriate number of broadcast stations can always be detected.

  Further, it further comprises table storage means for storing a table indicating the relationship between the number of broadcast stations indicated by the above-mentioned broadcast station information and the detection level, and the broadcast station information acquisition means includes the table stored in the table storage means. It is desirable to set the detection level by searching for the detection level corresponding to the number of broadcast stations indicated by the broadcast station information. Thereby, the detection level can be easily set according to the number of broadcasting stations.

  Also, vehicle position calculation means for calculating the vehicle position, map data storage means for storing map data including broadcast station information corresponding to the vehicle position, and a broadcast station corresponding to the vehicle position calculated by the vehicle position calculation means A navigation device comprising a broadcast station determination means for searching and outputting information based on map data is connected to the broadcast station information acquisition means, and the broadcast station information acquisition means It is desirable to obtain broadcast station information sent back in response to a request for information transmission. In the case of a receiver mounted on a vehicle, the number of broadcast stations that can be received changes corresponding to the vehicle position (traveling position). In such a case, the number of receivable broadcast stations corresponding to the installation position of the receiver is always accurately grasped by determining the number of receivable broadcast stations in the navigation device capable of detecting the vehicle position. Therefore, the detection level necessary for detecting an appropriate number of broadcasting stations can be set with high accuracy.

  Further, it is desirable that the broadcast station detection means described above detects a broadcast signal having a signal level equal to or higher than the detection level by sweeping the reception frequency in one direction. This makes it possible to detect an appropriate number of broadcasting stations in a so-called seek operation.

  Further, it is desirable that the broadcast station detection means described above detects a broadcast signal having a signal level equal to or higher than the detection level included in the reception band by sweeping the reception frequency over the entire range of the reception band. This makes it possible to detect an appropriate number of broadcast stations in a so-called autoselect operation.

  Further, the apparatus further comprises an adjacent interference detecting means for detecting the presence or absence of adjacent interference corresponding to the reception frequency, and the broadcast station detecting means is configured to detect adjacent interference even when a broadcast signal having a signal level equal to or higher than the detection level is detected. When the detection means detects the occurrence of adjacent interference, it is desirable to disable the detection of the broadcast signal. Thereby, it is possible to prevent erroneous detection of a broadcast signal when adjacent interference occurs.

  Further, it further comprises a multipath interference detection means for detecting the presence or absence of multipath interference occurrence corresponding to the reception frequency, the broadcast station detection means, even when a broadcast signal having a signal level equal to or higher than the detection level is detected, When the occurrence of multipath interference is detected by the multipath interference detection means, it is desirable to invalidate the detection of the broadcast signal. This can prevent erroneous detection of a broadcast signal when multipath interference occurs.

  Hereinafter, a receiver according to an embodiment to which the present invention is applied will be described in detail with reference to the drawings.

  FIG. 1 is a diagram illustrating a configuration of a receiver according to an embodiment. As shown in FIG. 1, the receiver of the present embodiment is for receiving a broadcast signal that is mounted on a vehicle and transmitted from a broadcast station, and includes a tuner unit 10, a demodulation unit 20, an amplifier 22, and a speaker 24. , A control unit 30, a memory 32, an operation unit 40, a display unit 42, an adjacent disturbance detection circuit 50, and a multipath disturbance detection circuit 52.

  The tuner unit 10 extracts only a predetermined frequency component from the broadcast signal that has reached the antenna 14, converts it into an IF (intermediate frequency) signal having a predetermined frequency band, and outputs the IF signal. For example, the tuner unit 10 is configured to include a high frequency amplifier, a mixer circuit, a local oscillator, an IF amplifier, an IF filter, and the like, and only frequency components to be received are extracted from the broadcast signal and subjected to frequency conversion. After that, the IF signal is output.

  In addition, the tuner unit 10 includes an S meter (signal meter) 12 that detects the received electric field strength of the broadcast signal corresponding to the IF signal. The S meter 12 outputs an S meter signal having a voltage level corresponding to the received electric field intensity, for example, by performing AM detection of the IF signal through an LPF (low pass filter).

  The demodulation unit 20 performs demodulation processing on the IF signal output from the tuner unit 10. For example, in the case of a receiver that receives AM broadcast, the AM detection processing is performed by the demodulator 20. In the case of a receiver that receives FM broadcast, the demodulation unit 20 performs FM detection processing and stereo demodulation processing. In addition, the receiver of this embodiment may be not only a radio receiver that receives an audio program, but also a television receiver that receives a program including video together with audio. Alternatively, the demodulating unit 20 may perform not only the demodulation process on the analog broadcast format broadcast signal but also the demodulation process on the digital broadcast system broadcast signal.

  The amplifier 22 amplifies the demodulated audio signal output from the demodulator 20 and drives the speaker 24. In FIG. 1, one speaker 24 is illustrated, but two or more speakers are provided when stereo sound is output.

  The control unit 30 controls the entire receiver. For example, the channel selection operation specifying the reception frequency and the broadcast station name, or sweeping the reception frequency in one direction (scanning) and stopping the sweep when a broadcast signal of a broadcast station above a predetermined detection level is detected. Control of the control unit 30 includes a seek operation for receiving the broadcast signal, an auto-select operation for sweeping the entire range of the reception band in one direction, and detecting broadcast signals of all broadcast stations having a predetermined detection level or higher. Is done by. In the present embodiment, control is performed to variably set the detection level in accordance with the number of receivable broadcasting stations in the seek operation or autoselect operation. The memory 32 is used to store one or a plurality of broadcast stations detected in the autoselect operation and to store information sent from the navigation device 80 (described later). The memory 32 is also used for storing a table indicating the relationship between the number of receivable broadcasting stations and the detection level, and this table is referred to when the detection level is set by the control unit 30. .

  The operation unit 40 is for instructing various operations to the receiver. In addition to a channel selection button, a volume control knob, etc., a seek button for instructing a seek operation and an auto S button for instructing an auto stop operation. Is equipped. The display unit 42 displays the operating state of the receiver, the selected broadcast station, the volume, and the like. For example, an LCD (liquid crystal display panel) or an LED (light emitting diode) is used.

  The adjacent interference detection circuit 50 detects the presence or absence of adjacent interference by an adjacent broadcast station (adjacent station) having a carrier frequency separated from the reception frequency by a predetermined frequency. When there is an adjacent station with a large transmission output, adjacent interference occurs when the reception frequency is included in a frequency range where the broadcast signal of the adjacent station is not sufficiently attenuated. The adjacent interference detection circuit 50 detects the presence or absence of this adjacent interference for each reception frequency, and outputs the detection result to the control unit 30.

  The multipath interference detection circuit 52 detects the presence or absence of multipath interference. For example, since noise due to multipath interference occurs during stereo demodulation of an FM broadcast signal, the presence or absence of multipath interference can be detected by detecting a high-frequency distortion component of a 19 kHz pilot signal included in the stereo composite signal. it can.

  A navigation device 80 is connected to the receiver described above. The navigation device 80 performs various navigation operations, and includes a map data storage unit 82, a vehicle position calculation unit 84, and a broadcast station determination unit 86. A GPS device 90 is connected to the navigation device 80. The GPS device 90 includes a GPS antenna and a calculation unit that analyzes radio waves of satellites received by the GPS antenna, and outputs a vehicle position signal indicating a vehicle position (longitude, latitude).

  The map data storage unit 82 stores map data necessary for various navigation operations such as map display and facility search. For example, in addition to the case where a disk-type recording medium such as a CD-ROM or DVD-ROM is used, a case where a hard disk device is used, map data required for navigation operation is distributed from a predetermined map data distribution center, a semiconductor memory, etc. The case where it stores in is considered. Further, the map data includes information regarding the number of broadcast stations corresponding to the vehicle position.

  The vehicle position calculation unit 84 calculates the vehicle position based on the vehicle position signal output from the GPS device 90. For example, a map matching process for comparing a travel locus with a road shape on a map is performed, and an accurate vehicle position is calculated.

  The broadcast station determination unit 86 searches the map data (part relating to the number of broadcast stations) stored in the map data storage unit 82 based on the vehicle position calculated by the vehicle position calculation unit 84, and is installed in the vehicle. The number of broadcast stations that can receive the broadcast signal by the receiver is determined. Information indicating the number of broadcast stations (broadcast station information) obtained by this determination is output toward the control unit 30 of the receiver.

  The control unit 30 described above is a broadcasting station information acquisition unit and detection level setting unit, the S meter 12, the control unit 30 is a broadcasting station detection unit, the tuner unit 10, the demodulation unit 20, the amplifier 22, the speaker 24, and the control unit 30. Each corresponds to a broadcast signal receiving means. Further, the memory 32 is a table storage unit, the vehicle position calculation unit 84 is a vehicle position calculation unit, the map data storage unit 82 is a map data storage unit, the broadcast station determination unit 86 is a broadcast station determination unit, and an adjacent disturbance detection circuit. Reference numeral 50 corresponds to the adjacent interference detection means, and the multipath interference detection circuit 52 corresponds to the multipath interference detection means.

  The receiver of the present embodiment has such a configuration. Next, a seek operation and an autoselect operation performed by the receiver will be described.

  FIG. 2 is a flowchart showing a seek operation performed by the receiver. The control unit 30 determines whether or not a seek operation has been instructed (step 100). If this instruction is not performed, a negative determination is made and this determination is repeated. The control unit 30 performs this determination by monitoring whether or not the seek button provided in the operation unit 40 is pressed. If the seek button is pressed, the control unit 30 makes an affirmative determination and then performs navigation. The broadcast station determination unit 86 in the apparatus 80 is inquired of the broadcast station information, that is, the transmission of the broadcast station information is requested (step 101). Thereafter, the control unit 30 determines whether broadcast station information has been sent from the navigation device 80 (step 102), and if not, makes a negative determination and repeats this determination.

  Further, when broadcast station information is sent from the navigation device 80, an affirmative determination is made in the determination of step 102, and then the control unit 30 sets a detection level in the seek operation based on the received broadcast station information. (Step 103). Broadcast station information indicates the number of broadcast stations that can be received at the traveling position of a vehicle equipped with a receiver. When this number is large, the detection level is high, and conversely, when this number is small, the detection level is high. Is set low. In a receiver mounted on a vehicle traveling around a large city, there are many receivable broadcast stations, and there are many broadcast stations having a large transmission output, so if the detection level is not set high, Broadcast stations are frequently detected during a seek operation, and it is difficult to reach a broadcast station that desires reception. By the way, considering the general usage of a receiver, there are many cases where it is desired to listen to a program of a broadcasting station having a large transmission output and low noise around a large city. For this reason, by setting the detection level higher and reducing the number of broadcast stations detected by the seek operation, the desired broadcast station can be found more quickly. On the other hand, for receivers installed in vehicles running in areas where the number of broadcast stations is small and the transmission output of broadcast signals is low, if the same detection level is set as in the vicinity of large cities, the broadcast signals of most broadcast stations Detection level becomes lower than the set value, and the number of broadcast stations that can be received by the seek operation decreases. For this reason, by setting the detection level to a low level and increasing the number of broadcast stations detected by the seek operation, it becomes possible to reliably search for the desired broadcast station.

  Next, the control unit 30 scans the reception frequency in one direction (step 104), and determines whether there is a broadcast signal whose S meter signal level is equal to or higher than the detection level (step 105). While such a broadcast signal is not detected, a negative determination is made in this determination, the detection of the broadcast signal is invalidated, and the process returns to step 104 to continue the one-way scanning operation.

  Further, when a broadcast signal whose level of the S meter signal is equal to or higher than the detection level is detected, an affirmative determination is made in the determination of step 105, and then the control unit 30 detects adjacent interference or multipath by the adjacent interference detection circuit 50. It is determined whether multipath detection is performed by the interference detection circuit 52 (step 106). If adjacent interference or multipath is detected, an affirmative determination is made in the determination in step 106, the detection of the broadcast signal is invalidated, and the flow returns to step 104 to continue the one-way scanning operation.

  If adjacent interference does not cause multipath, a negative determination is made in the determination in step 106, and then the control unit 30 stops the scanning operation of the reception frequency (step 107), and the S meter signal Control is performed to receive a broadcast signal whose level is equal to or higher than the detection level (step 108).

  FIG. 3 is a flowchart showing an autoselect operation performed by the receiver. The control unit 30 determines whether or not an auto-select operation has been instructed (step 200). If this instruction is not performed, a negative determination is made and this determination is repeated. The control unit 30 performs this determination by monitoring whether or not the auto-select (auto S) button provided in the operation unit 40 is pressed. If the auto-select button is pressed, an affirmative determination is made. Next, the broadcast station information is inquired of the broadcast station determination unit 86 in the navigation device 80 (step 201). Thereafter, the control unit 30 determines whether or not broadcast station information has been sent from the navigation device 80 (step 202), and if not, makes a negative determination and repeats this determination.

  When broadcast station information is sent from the navigation device 80, an affirmative determination is made in the determination of step 202, and then the control unit 30 sets a detection level in the autoselect operation based on the received broadcast station information. (Step 203). This detection level setting is performed in the same manner as the detection level setting in the seek operation described above. That is, in the vicinity of a large city, an appropriate number of broadcasting stations can be recorded in the memory 32 by setting the detection level higher and reducing the number of broadcasting stations detected by the autoselect operation. . On the other hand, in an area where the number of broadcasting stations is small, the detection level is set to a low level, and the number of broadcasting stations detected by the autoselect operation is increased, so that the number of broadcasting stations equal to that in the vicinity of a large city is stored in the memory 32. Will be able to record.

  Next, the control unit 30 scans the reception frequency in one direction from the lower limit value to the upper limit value of the reception band (step 204), and whether or not there is a broadcast signal whose S meter signal level is equal to or higher than the detection level. Is determined (step 205). When such a broadcast signal is detected, an affirmative determination is made, and then the control unit 30 performs adjacent interference detection by the adjacent interference detection circuit 50 or multipath detection by the multipath interference detection circuit 52. It is determined whether or not there is (step 206). If no adjacent interference or multipath occurs, a negative determination is made, and the control unit 30 registers the detected broadcast station in the memory 32 (step 207).

  In addition, when a broadcast signal whose level of the S meter signal is equal to or higher than the detection level is not detected (negative determination in the determination of step 205), or when adjacent interference or multipath is occurring (positive determination in the determination of step 206), Alternatively, when the registration process ends, the control unit 30 next determines whether or not the reception frequency has reached the upper limit value of the reception band (step 208). If not, a negative determination is made, and the process returns to step 204 to continue the one-way scanning operation.

  When the reception frequency reaches the upper limit value of the reception band, an affirmative determination is made in the determination in step 208, and then control for receiving the broadcast signal of the registered broadcast station is performed (step 209). For example, control is performed to receive the broadcast signal of the last detected broadcast station.

  Setting a certain detection level is not preferable because many broadcast stations are detected in the vicinity of a large city with many broadcast stations, but almost no broadcast stations are detected in a region with few broadcast stations. However, like the receiver of this embodiment, by setting the detection level according to the number of receivable broadcast stations, it is possible to avoid such a situation and always detect an appropriate number of broadcast stations. it can.

  The memory 32 stores a table indicating the relationship between the number of broadcast stations indicated by the broadcast station information and the detection level. The control unit 30 refers to the table stored in the memory 32 and searches for the detection level corresponding to the number of broadcast stations indicated by the broadcast station information, thereby setting the detection level. The detection level can be easily set according to the number.

  In addition, when mounted on a vehicle like the receiver of the present embodiment, the number of receivable broadcasting stations changes corresponding to the vehicle position (traveling position). In such a case, the number of receivable broadcast stations corresponding to the installation position of the receiver is always accurately grasped by determining the number of receivable broadcast stations in the navigation device 80 capable of detecting the vehicle position. This makes it possible to set the detection level necessary for detecting an appropriate number of broadcasting stations with high accuracy.

  In addition, the control unit 30 performs a seek operation for detecting a broadcast signal having a signal level equal to or higher than the detection level by scanning the reception frequency in one direction, whereby an appropriate number of broadcast stations can be used in the seek operation. Can be detected.

  Further, the control unit 30 performs an auto-select operation for detecting a broadcast signal having a signal level equal to or higher than the detection level included in the reception band by sweeping the reception frequency for the entire range of the reception band. An appropriate number of broadcast stations can be detected in the autoselect operation.

  In addition, the adjacent interference detection circuit 50 and the multipath interference detection circuit 52 are provided to detect the presence or absence of adjacent interference and multipath interference, and when the occurrence of these interferences is detected, the detection of the broadcast signal is invalidated. It is possible to prevent erroneous detection of a broadcast signal when adjacent interference or multipath interference occurs.

  In addition, this invention is not limited to the said embodiment, A various deformation | transformation implementation is possible within the range of the summary of this invention. In the above-described embodiment, the broadcast station information is acquired from the navigation device 80. However, the user may directly input the broadcast station information using the operation unit 40. For example, three options, “large”, “normal”, and “low”, are displayed on the display unit 42 and the user operates the operation unit 40 to receive at that time. One of these three options is selected in consideration of the number of broadcasting stations corresponding to the place where the machine is installed. The control unit 30 can set a detection level capable of detecting an appropriate number of broadcast stations by referring to the table of the memory 32 based on the number of broadcast stations corresponding to the selected option.

It is a figure which shows the structure of the receiver of one Embodiment. It is a flowchart which shows the seek operation | movement performed by a receiver. It is a flowchart which shows the autoselect operation | movement performed by a receiver.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Tuner part 12 S meter 14 Antenna 20 Demodulation part 22 Amplifier 24 Speaker 30 Control part 32 Memory 40 Operation part 42 Display part 50 Adjacent disturbance detection circuit 52 Multipath disturbance detection circuit 80 Navigation apparatus 82 Map data storage part 84 Vehicle position calculation part 86 Broadcasting station determination unit 90 GPS device

Claims (7)

Broadcast station information acquisition means for acquiring broadcast station information indicating the number of receivable broadcast stations;
Detection level setting means for setting a detection level for detecting a broadcast signal based on the broadcast station information;
Broadcast station detection means for detecting a broadcast signal having a signal level equal to or higher than the detection level;
Broadcast signal receiving means for receiving a broadcast signal detected by the broadcast station detecting means;
A receiver comprising: In claim 1,
A table storage means for storing a table indicating the relationship between the number of broadcast stations indicated by the broadcast station information and the detection level;
The broadcast station information acquisition means refers to the table stored in the table storage means, and searches for the detection level corresponding to the number of broadcast stations indicated by the broadcast station information, thereby obtaining the detection level. A receiver characterized by setting. In claim 1 or 2,
Vehicle position calculation means for calculating a vehicle position, map data storage means for storing map data including the broadcasting station information corresponding to the vehicle position, and the broadcast corresponding to the vehicle position calculated by the vehicle position calculation means A navigation device comprising a broadcasting station determination means for searching for and outputting station information based on the map data, and connected to the broadcasting station information acquisition means;
The broadcast station information acquisition means acquires the broadcast station information sent back in response to a request for transmission of the broadcast station information to the broadcast station determination means. In any one of Claims 1-3,
The broadcast station detection means detects a broadcast signal having a signal level equal to or higher than the detection level by sweeping a reception frequency in one direction. In any one of Claims 1-3,
The broadcast station detecting means detects a broadcast signal having a signal level equal to or higher than the detection level included in the reception band by sweeping the reception frequency over the entire range of the reception band. In any one of Claims 1-5,
It further comprises adjacent interference detection means for detecting the presence or absence of adjacent interference occurrence corresponding to the reception frequency,
Even when the broadcast station detection means detects a broadcast signal having a signal level equal to or higher than the detection level, when the adjacent disturbance detection means detects the occurrence of the adjacent disturbance, the broadcast station detection means detects the broadcast signal. A receiver characterized by being disabled. In any one of Claims 1-6,
Multipath interference detection means for detecting the presence or absence of occurrence of multipath interference corresponding to the reception frequency,
Even when the broadcast station detection means detects a broadcast signal having a signal level equal to or higher than the detection level, when the multipath interference detection means detects the occurrence of multipath interference, the broadcast station detection means A receiver characterized by invalidating detection.

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