JP3959187B2 - In-vehicle receiver - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a vehicle-mounted receiving device having a network follow function, and more particularly to effective use of a sub-tuner in a good reception state such as a strong electric field area.
[0002]
[Prior art]
In the in-vehicle receiving device, when the reception level of a broadcasting station that is currently received during traveling decreases, another broadcasting station that broadcasts the same content is searched (searched), and a broadcasting station with a high reception level is searched. Some have a network follow function for switching to a reception frequency and an FM multiple reception function for receiving traffic information and the like.
[0003]
FIG. 6 is a block diagram showing a configuration of a conventional in-vehicle receiving apparatus. Hereinafter, it demonstrates according to a figure.
[0004]
A distributor 91 distributes broadcast waves received by the antenna to the main tuner 92, the sub tuner 82, and the FM multiplex tuner 62. A main tuner 92 receives a broadcast wave of a broadcasting station that broadcasts the content desired by the listener, detects and demodulates it, and outputs it to the audio output unit 95. Reference numeral 93 denotes a PLL circuit for performing tuning processing so that the main tuner 92 can receive a broadcast wave of a predetermined frequency (first frequency f1) according to an instruction from the control unit 94, and is used as a mixer in a superheterodyne tuner. This circuit outputs a signal having a frequency corresponding to the reception frequency and converts a broadcast wave to be received into an intermediate frequency. 94 is a control unit composed of a microcomputer or the like that compares the reception levels of the broadcast waves received by the main tuner 92 and the sub tuner 82 and sets the reception frequency of the main tuner 92 via the PLL circuit 93 based on the result. It is. Reference numeral 95 denotes an audio output unit that amplifies an audio signal detected and demodulated by the main tuner 92 and outputs the amplified signal to a speaker. Reference numeral 71 denotes a comparator for comparing the broadcast content received by the main tuner 92 and the broadcast content received by the sub tuner 82 to determine whether or not the content is the same broadcast content. A sub tuner 82 receives a broadcast wave of another reception frequency (second frequency f 2) having the same broadcast content as the main tuner 92, detects it, and compares it with the reception level of the main tuner 92. Reference numeral 83 denotes a PLL circuit for performing tuning processing so that the sub tuner 82 can receive a broadcast wave of a predetermined frequency in accordance with an instruction from the control unit 94. Reference numeral 62 denotes an FM multiplex tuner that receives FM multiplex broadcast waves such as traffic information and outputs the FM multiplex broadcast wave to the FM multiplex receiving circuit 65. Reference numeral 63 denotes a PLL circuit for performing tuning processing so that the FM multiplex tuner 62 can receive a broadcast wave of a predetermined frequency in accordance with an instruction from the control unit 94. A multiplex receiving circuit 65 separates multiplexed data from the received FM multiplex broadcast wave and converts it into character data or the like. Reference numeral 66 denotes a display unit composed of a liquid crystal display or the like for displaying received character data.
[0005]
In the network follow, when the listener receives the broadcast by setting the main tuner 92 to the reception frequency of the desired broadcast station, the sub tuner 82 broadcasts the same content as the broadcast station being received by the main tuner 92. I always search for broadcast stations. Whether the broadcast contents are the same or not is determined by comparing the detection outputs of the main tuner 92 and the sub tuner 82 by the comparator 71. Then, the control unit 94 compares the reception level of the main tuner 92 with the reception level of the sub tuner 82 if the broadcast content is the same. If the reception level of the main tuner 92 is higher, the reception is continued at the current reception frequency. If the reception level of the sub tuner 82 is higher, the reception frequency of the main tuner 92 with respect to the PLL circuit 93 is increased. An instruction is given to change (frequency f1) to the reception frequency (frequency f2) of the sub tuner 82. In this way, the reception frequency of the main tuner 92 is always changed so that a broadcast wave with a high reception level of the same broadcast content can be received.
[0006]
On the other hand, since the reception frequency of the audio broadcast that the listener wants to receive does not necessarily match the reception frequency of the traffic information multiplexed in the FM broadcast, the broadcast received by the FM multiplex tuner 62 when receiving the traffic information. Multiplexed data is separated from the wave (third frequency f3), converted into character data by the FM multiplex receiving circuit 65, and displayed on the display unit 66 as characters.
[0007]
[Problems to be solved by the invention]
By comparing the reception levels received by the main tuner 92 and the sub tuner 82 and setting the reception frequency so that the reception level of the main tuner 92 is higher, it is possible to always receive well even if the driving environment changes. It becomes like this.
[0008]
However, when FM multiplex reception is performed by a conventional in-vehicle receiving apparatus, three tuners of a main tuner 92, a sub tuner 82, and an FM multiplex tuner 62 are required. However, when traveling in a region with a strong electric field strength such as a metropolitan area, the reception level of the main tuner 92 is sufficient even if the reception level of the main tuner 92 is lower than the reception level of the sub-tuner 82, for example. In many cases, good reception is possible without changing the reception frequency. For this reason, it is often unnecessary to search for the same broadcasting station, compare the reception level, and change the reception frequency, and the sub-tuner 82 becomes useless.
[0009]
An object of the present invention is to provide an in-vehicle receiver that can effectively save a tuner by effectively using a search sub-tuner in a strong electric field region or the like.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, the present invention has a main tuner for receiving a broadcast of a desired broadcast station, and a sub-tuner for searching for a broadcast station having the same broadcast content as the desired broadcast station by sweeping the frequency. In a vehicle-mounted receiving device having a network follow function for receiving a broadcast from a broadcasting station in the same broadcast content and having a good reception state when the reception state by the main tuner deteriorates, the reception level of the broadcast wave received by the main tuner is previously set When the reception level is higher than a set reception level, the sub-tuner is provided with a diversion means for stopping the search operation for the same broadcasting station and operating the sub-tuner with another reception function.
[0011]
In addition, there is a main tuner that receives a broadcast of a desired broadcast station, and a sub tuner that searches for a broadcast station having the same broadcast content as the desired broadcast station by sweeping the frequency, and the reception state by the main tuner has deteriorated In a vehicle-mounted receiving device having a network follow function for receiving broadcasts from broadcast stations in good reception with sometimes the same broadcast content, position detection means for detecting the position of the vehicle, and the electric field strength for each broadcast station is a predetermined value or more When a strong electric field area has a stored electric field intensity database, and the position of the vehicle detected by the position detection means is within the strong electric field area stored in the electric field intensity database, the same broadcast of the sub tuner A diversion means for stopping the station search operation and operating the sub-tuner with another reception function is provided.
[0012]
【Example】
FIG. 1 is a block diagram showing the configuration of a vehicle-mounted receiving apparatus according to the first embodiment of the present invention. Hereinafter, it demonstrates according to a figure.
[0013]
Reference numeral 11 denotes a distributor that distributes broadcast waves received by the antenna to the main tuner 12 and the sub tuner 22. A main tuner 12 receives a broadcast wave of a broadcasting station that broadcasts the content desired by the listener, detects and demodulates it, and outputs it to the audio output unit 15, and a signal indicating the received electric field strength (reception level) (For example, a tuning signal, that is, an output signal envelope detection, rectified and smoothed signal of the intermediate frequency amplification stage) is output to the control unit 14. Reference numeral 13 denotes a PLL circuit for performing tuning processing so that a broadcast wave having a frequency (first frequency f1) to be received by the main tuner 12 can be received by an instruction from the control unit 14. This is a circuit that supplies a signal having a frequency difference between the frequency to be received and the intermediate frequency to the mixing circuit in the main tuner 12. Reference numeral 14 denotes a control unit configured by a microcomputer or the like that compares the reception levels of broadcast waves received by the main tuner 12 and the sub tuner 22 and sets the reception frequency of the main tuner 12 via the PLL circuit 13 based on the result. It is. An audio output unit 15 amplifies the audio signal detected and demodulated by the main tuner 12 and outputs the audio from the speaker. Reference numeral 16 denotes a comparator for comparing the broadcast content received by the main tuner 12 and the broadcast content received by the sub-tuner 22 to determine whether or not they are the same broadcast content. The contents of the broadcast are compared by comparing the tuning signals. Reference numeral 22 denotes a sub-tuner for searching for a broadcast wave of another reception frequency (second frequency f2) having the same broadcast content as that of the main tuner 12, and has the same configuration as the main tuner 12 and has the same detection output and the like. A signal indicating the electric field strength is used for the comparison and used for comparison. The sub tuner 22 operates as an FM multiplex tuner when no search is performed. Reference numeral 23 denotes a PLL circuit for performing tuning processing so that the sub-tuner 22 can receive a broadcast wave of a predetermined frequency according to an instruction from the control unit 14, and has the same configuration as the PLL circuit 13. Reference numeral 25 denotes an FM multiplex receiving circuit that separates multiplexed data from received FM multiplex broadcast waves and converts it into character data or the like. Reference numeral 26 denotes a display unit composed of a liquid crystal display or the like for displaying character data converted by the FM multiplex receiving circuit 25.
[0014]
FIG. 2 is a flowchart of processing performed by the control unit of the in-vehicle receiving device according to the first embodiment of the present invention. Hereinafter, it demonstrates according to a figure. This process is repeatedly executed while the receiving apparatus is operating.
[0015]
In step S11, a tuner reception process, that is, a process of setting the reception frequency of the main tuner 12 to a predetermined frequency f1 is performed in order to enable the listener to listen to the desired broadcast content, and the process proceeds to step S12. In step S12, the reception level is detected, and the process proceeds to step S13. That is, the level of the detection output received by the main tuner 12 is detected. In step S13, it is determined whether or not the reception level is higher than the comparison level Vf registered in the memory. If the reception level is higher than the comparison level Vf, the process proceeds to step S14. If the reception level is lower than the comparison level Vf, the process proceeds to step S15. Move. The comparison level Vf is a level at which a good reception state can be maintained, and can be set by the manufacturer of the receiving apparatus or by the user.
[0016]
In step S14, the sub-tuner is used for purposes other than network follow, and the process ends. That is, if the reception level of the main tuner 12 is higher than the comparison level Vf, it can be determined that the reception state is good, and switching to the broadcasting station with the same broadcast content is not necessary, so the network follow-up operation of the sub tuner 22 is stopped. . Then, in order to effectively use the sub-tuner 22 that is no longer used for network follow, the reception frequency is set to the frequency f3 of the broadcasting station that performs FM multiplex broadcasting so that FM multiplex broadcasting can be received (FM multiplex reception). It is determined whether or not the multiplex broadcast is based on the multiplex data detection result by the circuit 25, and the reception frequency is sequentially changed and the FM multiplex broadcast is received until the FM multiplex broadcast is found.
[0017]
In step S15, the sub-tuner 22 is set to be used for network follow-up, and this process is terminated. That is, a broadcast station that performs the same broadcast content as that of the main tuner 12 is searched, and the reception level (at the frequency f1) of the main tuner 12 and the reception level (at the frequency f2) of the sub tuner 22 are compared in the control unit 14. . If the reception level of the main tuner 12 is higher, the reception is continued as it is (frequency f1). If the reception level of the sub tuner 22 is higher, the reception frequency (frequency f1) of the main tuner 12 is changed to the reception frequency (frequency f2) of the sub tuner 22. In this way, network follow is performed so that the broadcast wave with the higher reception level is always received. Note that once the reception frequency is changed to f2 by network follow, after that, if the reception level of the second broadcasting station is higher than the predetermined reception level, it is not necessary to perform network follow thereafter, so the sub tuner 22 is multiplexed. Can be diverted to broadcast reception. In addition, when the reception level of the first and second broadcasting stations is lower than the predetermined reception level, the network follower is constantly used by using the sub tuner 22, and the sub tuner 22 cannot be diverted to another. .
[0018]
In this way, in a strong electric field strength region, the sub-tuner 22 can be used (reused) without providing a dedicated tuner for receiving FM multiplex broadcasting, and the receiver can be reduced in size and cost. Can be realized. In other words, three tuners that are normally required to realize the network follow and FM multiplex broadcast receiving functions can be realized with two tuners in this embodiment.
[0019]
As described above, in this embodiment, when a vehicle is traveling in an area where reception is good without network follow-up, the sub-tuner for searching broadcast stations having the same broadcast content is used as a tuner for receiving FM multiplex broadcasts. Since it is used effectively, one tuner can be omitted without causing much functional degradation.
[0020]
FIG. 3 is a block diagram showing the configuration of the in-vehicle receiver of the second embodiment of the present invention. Hereinafter, it demonstrates according to a figure.
[0021]
Reference numeral 41 denotes a GPS receiver that detects a vehicle position using radio waves from an artificial satellite. Reference numeral 42 denotes a map database in which map information is recorded. Reference numeral 43 denotes an electric field strength database in which regions where electric field strength is strong are recorded for each broadcasting station (broadcasting frequency). A navigation control unit 44 determines a vehicle position based on the output of the GPS receiver 41 and the map database 42, and determines whether or not the specified vehicle position is an area having a strong electric field strength. The distributor 11, the main tuner 12, the PLL circuits 13 and 23, the sub tuner 22, the control unit 14, the audio output unit 15, the comparator 16, the FM multiplex reception circuit 25, and the display unit 26 are the same as in the first embodiment. Therefore, the same number is assigned and the description is omitted.
[0022]
FIG. 4 is a flowchart of processing performed by the control unit 14 of the in-vehicle receiving apparatus according to the second embodiment of the present invention. FIG. 5 is a diagram showing the relationship between the contents of the electric field intensity database and the vehicle position, where (a) is a strong electric field region of the first broadcasting station, (b) is a strong electric field region of the second broadcasting station, and (c) is The vehicle position, (d) is the relationship between the strong electric field area of both broadcast stations and the vehicle position. Hereinafter, it demonstrates according to a figure. This process is repeatedly executed while the receiving apparatus is operating.
[0023]
In step S21, the vehicle position is detected and the process proceeds to step S22. That is, the vehicle position (point A, point B, point C) is specified based on the GPS receiver 41 and the map database 42. Note that the map database 42 is not necessarily required to match the vehicle position with the electric field intensity database 43. If the strong electric field area of the electric field intensity database 43 is indicated by latitude and longitude, the vehicle position is indicated by latitude and longitude. It may be possible to specify.
[0024]
In step S22, it is determined whether or not the specified vehicle position is within the strong electric field area. If the vehicle position is within the strong electric field area, the process proceeds to step S23, and if not, the process proceeds to step S24. That is, the vehicle position (for example, point A in FIG. 5C) specified by the GPS receiver 41 is a strong electric field area where the good reception state of the electric field intensity database 43 can be obtained (the currently receiving broadcast station is the first station). In the case of one broadcasting station, it is determined whether or not it belongs to the shaded portion in the strong electric field area of the first broadcasting station in FIG. As shown in FIGS. 5 (a) and 5 (b), the electric field strength database 43 is a map based on latitude and longitude based on latitude and longitude, as shown in FIGS. 5 (a) and 5 (b). The strong electric field range may be recorded corresponding to the latitude and longitude). Note that the second broadcast station in FIG. 5B is a network follow station having the same broadcast contents as the first broadcast station.
[0025]
In step S23, the sub-tuner is set to be used for other than network follow, and this process is finished. That is, the vehicle is traveling in the strong electric field area of the first broadcasting station (the position of point A in FIG. 5D), and the broadcast state of the first broadcasting station received by the main tuner 12 is received. Since the network follow operation is not necessary, the network follow operation of the sub tuner 22 is stopped. In order to effectively use the sub tuner 22 that is no longer used, in step S24, the reception frequency is set to the frequency f3 of the broadcasting station that is performing FM multiplex broadcasting so that FM multiplex broadcasting can be received. Set up to use for network follow and finish this process. That is, it is determined that the vehicle is traveling in the weak electric field region (the position of point B or C in FIG. 5D) and the reception state of the broadcast wave received by the main tuner 12 may deteriorate. it can. Therefore, a broadcast station that performs the same broadcast content as the main tuner 12 is searched, and the reception level (at the frequency f1) of the main tuner 12 and the reception level (at the frequency f2) of the sub tuner 22 are compared in the control unit 14. . If the reception level of the main tuner 12 is higher, the reception is continued as it is (frequency f1). If the reception level of the sub tuner 22 is higher, the reception frequency (frequency f1) of the main tuner 12 is changed to the reception frequency (frequency f2) of the sub tuner 22. In this way, network follow is performed so that the broadcast wave with the higher reception level is always received. When the vehicle is at point B, once the reception frequency is changed to f2 by network follow, it will be in the strong electric field area of the second broadcasting station and the vehicle will not go out of this area. As long as there is no need to perform network follow, the sub tuner 22 can be diverted to receive multiplex broadcasts. When the vehicle is at point C, the sub-tuner 22 is constantly used for network follow-up in the weak electric field area of both the first and second broadcasting stations. It cannot be diverted.
[0026]
In this way, in a strong electric field strength region, the sub-tuner 22 can be used (reused) without providing a dedicated tuner for receiving FM multiplex broadcasting, and the receiver can be reduced in size and cost. Can be realized. In other words, three tuners that are normally required to realize the network follow and FM multiplex broadcast receiving functions can be realized with two tuners in this embodiment.
[0027]
As described above, in this embodiment, the vehicle position is specified by the GPS system, and the position is compared with the electric field intensity database. Since the sub-tuner for searching for the broadcasting station is effectively used as a tuner for receiving FM multiplex broadcasting, one tuner can be omitted without causing much functional degradation.
[0028]
In each of the above embodiments, the sub-tuner is used for reception of FM multiplex broadcasting, but it can also be used for processing for spatial diversity operation for countermeasures against multipath noise.
[0029]
【The invention's effect】
As described above, in the present invention, in a strong electric field area or the like, when the reception state is so good that network follow-up is not necessary, the sub-tuner for searching for a broadcast station having the same broadcast content is effectively used, An in-vehicle receiver that can save a tuner can be provided.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of a vehicle-mounted receiving device according to a first embodiment of the present invention.
FIG. 2 is a flowchart of processing performed by a control unit of the in-vehicle receiving device according to the first embodiment of this invention.
FIG. 3 is a block diagram showing a configuration of a vehicle-mounted receiving device according to a second embodiment of the present invention.
FIG. 4 is a flowchart of processing performed by a control unit of the in-vehicle receiving device according to the second embodiment of the present invention.
FIG. 5 is a diagram showing the relationship between the contents of an electric field strength database and vehicle positions.
FIG. 6 is a block diagram showing a configuration of a conventional in-vehicle receiving device.
[Explanation of symbols]
11... Distributor, 25... FM multiplex receiving circuit,
12 .... main tuner, 26 ... display,
22 .... sub tuner, 41 ... GPS receiver,
13, 23 ... PLL circuit, 42 ... Map database,
14 .... Control unit, 43 ... Field strength database,
15 ... Voice output unit 44 ... Navigation control unit,
16 .... Comparator.

Claims (2)

A main tuner that receives a broadcast of a desired broadcast station and a sub tuner that searches for a broadcast station having the same broadcast content as the desired broadcast station by sweeping the frequency, and is the same when the reception state of the main tuner deteriorates In a vehicle-mounted receiving device having a network follow function for receiving a broadcast of a broadcast station in a good reception state with broadcast contents,
When the reception level of the broadcast wave received by the main tuner is higher than a preset reception level, diversion means for stopping the same tuner search operation of the sub tuner and operating the sub tuner with another reception function. A vehicle-mounted receiving device comprising the vehicle-mounted receiving device. A main tuner that receives a broadcast of a desired broadcast station and a sub tuner that searches for a broadcast station having the same broadcast content as the desired broadcast station by sweeping the frequency, and is the same when the reception state of the main tuner deteriorates In a vehicle-mounted receiving device having a network follow function for receiving a broadcast of a broadcast station in a good reception state with broadcast contents,
Position detecting means for detecting the position of the vehicle;
Each broadcast station has an electric field strength database in which strong electric field areas having electric field strengths of a predetermined value or more are stored,
When the position of the vehicle detected by the position detecting means is within a strong electric field area stored in the electric field intensity database, the sub tuner is stopped from searching for the same broadcast station, and the sub tuner is set to another receiving function. A vehicle-mounted receiving device comprising a diverting device that operates on the vehicle.

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