JPH0578036U - Radio receiver - Google Patents

Abstract

(57) [Summary] [Purpose] The sweep sensitivity of the auto search is automatically switched in response to changes in reception conditions, such as day and night, to prevent accidental stoppage. [Structure] In response to the operation of the auto search switch 13b, the reception frequency is swept, and separately from the first reception circuit 2 that receives the broadcast of the broadcast station whose reception electric field strength is equal to or higher than the first level. The receiving circuit 3 is provided, and the second receiving circuit 3
The number of broadcasting stations having a reception electric field strength equal to or higher than the second level is counted within the reception frequency band of the first reception circuit 2. Corresponding to the count result, the first level of the first receiving circuit 2 is set to a value corresponding to either the local mode or the DX mode. by this,
Even if you are receiving in the DX mode during the daytime and the reception conditions are good at night and the DX mode causes an erroneous stop during an auto search, the erroneous stop occurs by automatically switching to the local mode. Can be prevented.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a radio receiver having a so-called auto-search function for sweeping a reception frequency and automatically receiving a broadcast from a broadcast station.

[0002]

[Prior Art]

 The auto search function sweeps the reception frequency in response to, for example, the operation of the listener's auto search button, and automatically detects and receives receivable broadcasting stations whose received electric field strength is above a predetermined level. Is a function to perform. Such an auto-search function is preferably carried out by a vehicle-mounted radio receiver installed in an automobile, for example, a preset broadcast that can be received in the living area while the listener is traveling outside the normal living area. It is preferably used when searching for a broadcast station that can be received in the area different from the station.

In realizing the auto search function as described above, in a typical conventional technique, two receiving modes for setting the predetermined level are switchable. The first reception mode is called, for example, the local mode, and is used in an area with a relatively high received electric field strength, such as an urban area, and the sweep operation is stopped for the transmission from a distant place where the received electric field strength is relatively low. In order to prevent this, the predetermined level is set relatively high. On the other hand, the second reception mode is called the DX mode, and the predetermined level is set to be relatively low so that the radio broadcasting can be received even in the area where the reception conditions are relatively bad such as in the mountain area. To be done. In this way, the optimum sweep operation is performed by switching the reception mode, that is, the predetermined level.

[0004]

[Problems to be solved by the device]

 In the above-mentioned conventional technique, in the area where the DX mode is optimal in the daytime, when the reception condition is improved at night and the broadcast of the distant broadcasting station can be received, even if it is outside the service area of the broadcasting station, The sweep operation stops by mistake. Therefore, it is necessary to switch the reception mode between daytime and nighttime, which complicates the operation.

An object of the present invention is to provide a radio receiver capable of properly maintaining the sweep sensitivity of the reception frequency and improving the operability.

[0006]

[Means for Solving the Problems]

 The present invention provides a first receiving means for sweeping a reception frequency in response to a tuning operation of a listener, and receiving a broadcast of a broadcasting station having a reception electric field strength of a first level or higher, which is predetermined, and the first receiving means. Second receiving means for detecting the number of receivable broadcasting stations whose receiving electric field strength is equal to or higher than a predetermined second level by sweeping the receiving frequency within the receiving frequency band, and the detection result of the second receiving means. And a level setting means for setting the first level in the first receiving means in response.

[0007]

[Action]

 According to the present invention, the first receiving means sweeps the receiving frequency in response to the listener's tuning operation such as the operation of the auto search button, and the broadcasting station whose receiving electric field strength is above the predetermined first level. To receive the broadcast. As a result, when used as a vehicle, it can be suitably used for receiving a broadcast station for which the reception frequency is not preset, outside the normal living range of the listener.

A second receiving means is provided in association with the first receiving means, and the second receiving means is always or within a predetermined short time within the reception frequency band of the first receiving means. The reception frequency is swept every time, and the number of receivable broadcast stations whose reception electric field strength is equal to or higher than the second level set in advance is detected. Therefore, from this detection result, it is possible to determine whether the receiving place is a place with a relatively large number of receivable stations such as an urban area or a place with a small number of receivable stations such as a mountain area. ..

The detection result of the second receiving means is given to the level setting means, and the level setting means responds to the detection result, that is, in response to whether it is, for example, an urban area or a mountain area. , Setting a first level in the first receiving means. Therefore, it is possible to automatically set the optimum sweep sensitivity corresponding to the reception condition, and the reception condition is improved at night even in the place where the first level is set to be relatively low in the daytime. Then, when the number of receivable broadcasting stations increases, the first level is automatically set to a high level to prevent erroneous stop of the sweep operation for distant broadcasting stations. As a result, the setting operation of the first level becomes unnecessary, and the operability can be improved.

[0010]

【Example】

 FIG. 1 is a block diagram showing an electrical configuration of a radio receiver 1 according to an embodiment of the present invention. In this radio receiver 1, two receiving circuits 2 and 3 are provided. The reception signal received by the antenna 4 is input to the detection circuit 6 via the front end circuit 5 in the first reception circuit 2 and demodulated into an audio signal. The audio signal is given to the speaker 8 via the low-frequency amplifier circuit 7 and sonicated.

An S meter detection circuit 9 is provided in association with the front end circuit 5. The S meter detection circuit 9 receives an intermediate frequency output from the front end circuit 5 and outputs the intermediate frequency output. Is detected by direct current, and is output as a detection output indicating the received electric field strength to a processing circuit 11 which is realized by a microcomputer or the like and is a level setting means. Based on this S meter output, the processing circuit 11 outputs data such as N value to a phase lock loop (hereinafter abbreviated as PLL) circuit 10 in order to perform a tuning operation as described later.

A memory 12, an operation switch 13, and a display device 14 are provided in association with the processing circuit 11. In the memory 12, the reception frequency preset by the input operation from the operation switch 13 and the like are stored. In response to the tuning operation from the operation switch 13, the processing circuit 11 causes the front-end circuit 5 to perform a tuning operation based on the stored contents of the memory 12 and the display device 14 to receive the received frequency. Is displayed.

On the other hand, the second receiving circuit 3 is provided with a front end circuit 15, an S meter detecting circuit 16 and a PLL circuit 17 similar to the first receiving circuit 2. The processing circuit 11 constantly changes the N value of the PLL circuit 17 to sweep the tuning frequency of the front end circuit 15 within the reception frequency band of the first reception circuit 2 and set the reception electric field strength at each frequency to S. Reading is performed through the meter detection circuit 16, and the reception mode of the first reception circuit 2 is switched as described later in response to the read detection result.

That is, the processing circuit 11 responds to the operation of the preset switch 13 a in the operation switch 13 to read the N value of the reception frequency corresponding to the operated preset switch 13 a from the memory 12 and to the PLL circuit 10. Set. As a result, the tuning frequency of the front end circuit 5 becomes a value corresponding to the preset frequency and reception is performed.

When the auto search switch 13b is operated, the N value of the PLL circuit 10 is sequentially changed and the tuning frequency of the front end circuit 5 is swept. When this sweep operation detects that the received electric field strength detected through the S meter detection circuit 9 has reached a predetermined first level or higher, the sweep operation is stopped and reception at that frequency is performed. To do.

The first level is relatively high in the local mode, which is used in an area such as an urban area where many broadcasting stations having relatively high reception electric field strength can be received corresponding to the reception mode. It is set to a relatively low value in the DX mode, which is set and is preferably used in a region where the received electric field strength becomes weak. Such switching of the reception mode is performed as follows. By operating the cancel switch 13c of the operation switch 13, the local mode or the DX mode can be held in a selected state.

In the second receiving circuit 3, the processing circuit 11 changes the N value of the PLL circuit 17 to perform a sweeping operation, and the received electric field strength detected by the S meter detecting circuit 16 by this is a predetermined second value. Compared to the level. The second level is selected to be the same as or smaller than the level of the first level in the DX mode, for example. By such a sweeping operation, the number of broadcasting stations having the received electric field strength of the second level or more is a predetermined value M, for example, 20 or more, and the first receiving circuit 2 of Switch the reception mode. That is, when the number of broadcasting stations is the value M or more, the local mode is set, and when the number is less than the value M, the DX mode is set.

However, the switching of the reception mode as described above is performed when the auto search switch 13b is operated, and even if it is determined that the reception mode should be switched, the receiving broadcasting station is switched off without the operation of the listener. There is no replacement. Therefore, it does not happen that the broadcast which has been received until then is not received because the mode is switched to the local mode during the reception in the DX mode.

FIG. 2 is a flow chart for explaining the reception mode setting operation as described above. In step n1, it is determined whether or not the cancel switch 13c is operated, that is, whether or not the automatic reception mode switching function is selected. If not, the process proceeds to step n10 to be described later, and if so, the step Move to n2. At step n2, it is judged whether or not the counting operation of the number of broadcasting stations by the second receiving circuit 3 is completed, that is, whether or not the sweeping operation over the entire receiving frequency band of the first receiving circuit 2 is completed. If not, the process proceeds to step n3. At step n3, the N value of the PLL circuit 17 is updated, and at step n4, it is judged whether or not the received electric field strength at the updated N value is equal to or higher than the second level, and if so, After the number of stations is counted in step n5, the process proceeds to step n10, and if not, the process directly proceeds to step n10.

Steps n3 to n5 as described above are repeated, and when the sweep operation of the second receiving circuit 3 is completed in step n2, the process moves to step n6, and the number of broadcasting stations counted in step n5 is It is determined whether or not the value is equal to or more than the predetermined value M, and if so, in step n7, the reception mode is selected to the local mode, and then the process proceeds to step n10. If not, in step n8, the DX mode is selected. Mode is selected, the process proceeds to step n10. At step n10, after receiving an input operation from the preset switch 13a and other processing such as display control, the process returns to step n1.

As described above, in the radio receiver 1 according to the present invention, the number of broadcasting stations that can be received within the reception frequency band of the first receiving circuit 2 separately from the first receiving circuit 2 that receives a radio broadcast. A second receiving circuit for detecting the signal is provided, and the receiving mode of the first receiving circuit is switched between the local mode and the DX mode based on the detection result. Therefore, even in areas where DX mode reception is performed during the daytime, if the reception conditions are improved at night and reception in local mode is preferable, the reception mode is automatically switched, which is complicated. It is possible to prevent the erroneous stop of the sweep operation and to improve the operability without requiring any special operation.

In a so-called RDS type radio receiver which is put into practical use in Europe, etc., the frequency of a net station broadcasting the same content is read from the data transmitted together with the audio signal, Separately from the receiving circuit that demodulates the audio signal so that the broadcasting station currently receiving and the broadcasting station with the higher received electric field strength with the net station are received, it is already necessary to track the network station. Since one receiving circuit is provided, this receiving circuit may be used as the second receiving circuit 3 of the present invention.

[0023]

[Effect of the device]

 As described above, according to the present invention, in relation to the first receiving means for sweeping the reception frequency and automatically receiving the broadcast of the receivable broadcasting station whose reception electric field strength is equal to or higher than the predetermined first level, A second receiving means is provided for sweeping the receiving frequency within the receiving frequency band of the first receiving means, and detecting the number of receivable broadcasting stations whose receiving field strength is equal to or higher than a predetermined second level. The first level is set in response to the detection result.

Therefore, when the number of broadcasting stations is large, the first level is set to be relatively high, and so-called local broadcasting stations can be clearly received. Further, when the number of broadcasting stations is small, it is possible to receive even a distant broadcasting station whose reception electric field strength is relatively low. In this way, the sweep sensitivity of the first receiving means can be switched to perform the optimum sweep operation corresponding to the receiving condition. As a result, especially in a place where the number of stations that can be received in the daytime is small, even if the number of stations that can be received increases due to the improved reception conditions at night, the sweep operation will erroneously stop at stations with poor reception conditions. You can prevent that. In this way, it is possible to set the optimum sweep sensitivity corresponding to the reception conditions without complicated operations.

[Brief description of drawings]

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

FIG. 2 is a flowchart for explaining a reception mode setting operation of the radio receiver 1.

[Explanation of symbols]

 1 Radio receiver 2 1st receiving circuit 3 2nd receiving circuit 5,15 Front end circuit 6 Detection circuit 8 Speaker 9,16 S meter detection circuit 10,17 PLL circuit 11 Processing circuit 13 Operation switch 13a Preset switch 13b Auto search switch 13c Cancel switch

Claims (1)

[Scope of utility model registration request] 1. A first receiving means for sweeping a reception frequency in response to a tuning operation of a listener and receiving a broadcast of a broadcast station having a reception electric field strength of a first level or higher, which is predetermined, and the first reception. Second receiving means for sweeping the receiving frequency within the receiving frequency band of the means, and detecting the number of receivable broadcasting stations whose receiving electric field strength is equal to or higher than a predetermined second level; and the detection result of the second receiving means. And a level setting means for setting the first level in the first receiving means in response to the radio receiver.