JP3976596B2 - Broadcast receiver - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention seeks, for example, a frequency within a frequency band related to broadcast radio waves such as AM broadcast, and an AM having a seek function that stops the seek operation when the received frequency of the seek is determined to be an effective station. The present invention relates to a broadcast receiving apparatus such as a broadcast receiver.
[0002]
[Prior art]
Conventionally, such an AM broadcast receiver seeks to receive a frequency within a frequency band related to an AM broadcast radio wave, and stops the seek operation when it is determined that the received frequency of the seek is an effective station. A seek function is provided.
[0003]
According to such a conventional AM broadcast receiver, by using this seek function, all effective stations in the frequency band related to the broadcast wave of AM broadcast can be received with a simple operation.
[0004]
In general, AM broadcast radio waves have good propagation characteristics, and therefore, spurious interference in which broadcast radio waves interfere with each other generally occurs in a middle / strong input electric field region.
[0005]
This spurious interference is generated at a frequency that is a multiple of the reception frequency of an actual broadcasting station, a difference / sum frequency of a plurality of stations, etc. in a middle / strong input electric field region.
[0006]
[Problems to be solved by the invention]
However, according to the above-described conventional AM broadcast receiver, the seek operation is stopped when the seek reception is performed within the frequency band and it is determined that the received frequency of the seek is an effective station. When this occurs, the spurious frequency is erroneously determined as a valid station even though it is not a broadcast station, and the seek operation is stopped, causing an unnecessary stop of the seek operation. .
[0007]
Further, according to the conventional AM broadcast receiver, even if spurious interference occurs in the actual broadcast station reception frequency, the spurious frequency is the same as the actual broadcast station reception frequency. The spurious frequency will be judged as an effective station and the seek operation will be stopped. However, since the actual broadcasting station is an interference station that interferes with spurious interference, it cannot be said to be an effective station and is unnecessary. Stop of seek operation occurred.
[0008]
The present invention has been made in view of the above points, and an object of the present invention is to provide a broadcast receiving apparatus that can reliably prevent an unnecessary seek operation from being stopped due to spurious interference.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, the broadcast receiving apparatus of the present invention seeks a frequency within a frequency band related to a broadcast radio wave, and stops the seek operation when it is determined that the received reception frequency is a valid station. A broadcast receiving apparatus having a seek function, and when reception of broadcast radio waves is selected, seek reception is sequentially performed in the frequency band through the seek function, and whether or not the received electric field intensity at the received frequency exceeds a predetermined value. Receiving field strength determining means for determining whether or not the receiving field strength determining means determines that the receiving field strength exceeds a predetermined value, and receiving frequency storage means for storing the receiving frequency, and the receiving frequency Spurious prediction calculation means for calculating a spurious prediction frequency based on the reception frequency stored in the storage means, and the spurious prediction calculation means And spurious prediction storage means for storing a spurious predicted frequency, in the seek function, have a control means for prohibiting stopping of the seek operation in spurious predicted frequency stored in the spurious prediction storage unit, the spurious prediction calculating means Is a multiple frequency of the reception frequency stored in the reception frequency storage means, a sum frequency that is the sum of the reception frequencies stored in the reception frequency storage means, and the reception frequencies stored in the reception frequency storage means A first difference frequency that is the difference between the multiple frequencies, a second difference frequency that is the difference between the reception frequency stored in the reception frequency storage means and the multiple frequency, and a third difference frequency that is the difference between the multiple frequencies. The spurious predicted frequency is calculated .
[0010]
Therefore, according to the broadcast receiving apparatus of the present invention, when reception of broadcast radio waves is selected, the frequency within the frequency band is sequentially received, and it is determined that the received electric field strength at the received frequency exceeds a predetermined value. Then, the reception frequency is stored, the spurious prediction frequency is calculated based on the stored reception frequency, and the calculated spurious prediction frequency is stored in the spurious prediction storage unit, thereby the spurious prediction frequency. Since the stop of the seek operation by the seek function is prohibited, the unnecessary seek operation stop caused by spurious interference, for example, misinterpretation of an interference station or invalid station as a valid station is prevented. It can be surely prevented.
[0012]
Further , according to the broadcast receiving apparatus of the present invention, the spurious predicted frequency can be easily calculated based on the received frequency stored in the received frequency storage means.
[0013]
In the broadcast receiving apparatus of the present invention, the broadcast radio wave is an AM broadcast radio wave.
[0014]
Therefore, according to the broadcast receiving apparatus of the present invention, when the reception of the AM broadcast wave is selected, the frequency within the AM frequency band is sequentially received, and the received electric field strength at the received frequency exceeds a predetermined value. When the determination is made, the reception frequency is stored, the spurious prediction frequency is calculated based on the stored reception frequency, and the calculated spurious prediction frequency is stored in the spurious prediction storage means. Stopping the seek operation by the seek function with the predicted frequency as the reception frequency is prohibited. For example, miscommunication stations and invalid stations are erroneously determined as valid stations due to spurious interference that is likely to occur in AM broadcast radio waves. Stop of the unnecessary seek operation that occurs can be surely prevented.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an AM / FM broadcast receiver according to an embodiment of the broadcast receiver of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a schematic configuration inside an AM / FM broadcast receiver according to the present embodiment.
[0016]
An AM / FM broadcast receiver 1 shown in FIG. 1 includes a receiving antenna 11 that receives an incoming broadcast radio wave, a high-frequency amplifier circuit 12 that amplifies the broadcast radio wave received by the receiving antenna 11 as a broadcast signal, and local oscillation. A PLL circuit 13 that generates a signal, a mixer circuit 14 that converts the frequency of the broadcast signal that has been amplified by the high frequency amplifier circuit 12 and a local oscillation signal to an intermediate frequency signal, and an IF that amplifies the intermediate frequency signal An amplifier circuit 15, a detection circuit 16 for detecting the amplified intermediate frequency signal, an S meter detection circuit 17 for detecting the S meter voltage of the intermediate frequency signal from the IF amplifier circuit 15, and detection by the S meter detection circuit 17 The effective station detection circuit 18 for determining whether or not the currently receiving broadcast station is an effective station based on the S meter voltage, and various information A memory unit 19 for 憶, and a microcomputer 20 for controlling the entire AM / FM broadcast receiver 1.
[0017]
The microcomputer 20 variably controls the PLL circuit 13 to receive a seek within a frequency band related to the broadcast radio wave. When the received frequency is determined to be a valid station, the microcomputer 20 has a seek function to stop the seek operation. I have.
[0018]
For example, when the microcomputer 20 selects reception of AM broadcast waves when the power to the AM / FM broadcast receiver 1 is turned on or when the mode is changed from FM to AM, the microcomputer 20 sequentially seeks within the frequency band through the seek function. The effective station detection circuit 18 determines whether or not the received S meter of each reception frequency exceeds a predetermined value.
[0019]
When the effective station detection circuit 18 determines that the S meter exceeds the predetermined value, the memory unit 19 stores a reception frequency memory area 19A for storing the reception frequency and a prohibition setting for storing a spurious predicted frequency to be described later. And a memory area 19B.
[0020]
The microcomputer 20 calculates a spurious predicted frequency based on the received frequency stored in the received frequency memory area 19A, stores the calculated spurious predicted frequency in the prohibited setting memory area 19B, and stores it in the prohibited setting memory area 19B. The stop of the seek operation at the spurious predicted frequency is prohibited.
[0021]
FIG. 2 is an explanatory diagram briefly showing the calculation result of the spurious predicted frequency in the microcomputer 20.
[0022]
In FIG. 2, for example, as three broadcasting stations N0, N1, and N2, the receiving frequency of the broadcasting station N0 is 600 kHz, the receiving frequency of the broadcasting station N1 is 1000 kHz, and the receiving frequency of the broadcasting station N2 is 1500 kHz.
[0023]
As shown in FIG. 2A, a multiple frequency (double frequency Nn × 2, triple frequency Nn × 3) that is an integral multiple of the reception frequency of the broadcast station N0, broadcast station N1, and broadcast station N2 is the spurious predicted frequency. .
[0024]
As shown in FIG. 2B, the sum frequency (N0 + N1, N1 + N2, etc.), which is the sum of the two received frequencies of the broadcasting stations N0, N1, and N2, is the spurious predicted frequency.
[0025]
As shown in FIG. 2C, the first difference frequency (N0-N1, N1-N2, etc.), which is the absolute value of the difference between the two reception frequencies of the broadcast stations N0, N1, N2, is the spurious expected frequency. Become.
[0026]
As shown in FIG. 2D, the second difference frequency (N0−N0 × 2, N0−N0 × 3,...), Which is the absolute value of the difference between the reception frequency of the broadcast stations N0, N1, and N2 and the multiple frequency. Becomes the spurious prediction frequency.
[0027]
The third difference frequency (N0 × 2-N0 × 3, etc.), which is the absolute value of the difference between the multiple frequencies of the reception frequencies of the broadcasting stations N0, N1, and N2 shown in FIG. It becomes.
[0028]
The reception electric field strength determination means is the effective station detection circuit 18, the reception frequency storage means is the reception frequency memory area 19A, the spurious prediction storage means is the prohibition setting memory area 19B, the spurious prediction calculation means and the control means are the microcomputer 20. It is equivalent to.
[0029]
Next, the operation of the AM / FM broadcast receiver 1 showing this embodiment will be described. FIG. 3 is a flowchart showing the processing operation of the microcomputer 20 related to the spurious inhibition setting process of the AM / FM broadcast receiver 1 according to the present embodiment.
[0030]
The spurious prohibition setting process shown in FIG. 3 is a process in which, for example, a predicted spurious frequency is calculated in advance by a seek operation when the power is turned on, and the predicted spurious frequency is stored in the prohibition setting memory area 19B.
[0031]
In FIG. 3, the microcomputer 20 determines whether or not power-on to the AM / FM broadcast receiver 1 has been detected (step S11).
[0032]
If power-on to the AM / FM broadcast receiver 1 is detected, the audio mute is turned on (step S12), and a pre-seek operation is performed on the frequency within the AM frequency band (step S13).
[0033]
The microcomputer 20 detects the S meter at the frequency received in this pre-seek operation, and determines whether or not the S meter at this frequency exceeds the predetermined value through the effective station detection circuit 18 (step S14). . If it is determined that the frequency of the S meter exceeds the predetermined value, the reception frequency is stored in the reception frequency memory area 19A (step S15).
[0034]
The microcomputer 20 calculates a spurious predicted frequency based on the reception frequency stored in the reception frequency memory area 19A (step S16). Furthermore, since the AM reception frequency band is set to 530 kHz to 1710 kHz, only the spurious prediction frequency within this frequency band is extracted (step S17) as shown by the shaded area in FIG. This processing operation is terminated by storing the prohibition setting memory area 19B (step S18) and turning off the mute (step S19).
[0035]
If it is not detected in step S11 that power to the AM / FM broadcast receiver 1 has been detected, or if there is no frequency at which the S meter exceeds a predetermined value in step S14, this processing operation is terminated.
[0036]
According to the spurious prohibition setting process shown in FIG. 3, the reception frequency that is the frequency at which the S meter exceeds a predetermined value in the pre-seek operation is stored, the spurious prediction frequency is calculated based on these reception frequencies, and the spurious prediction frequency is calculated. The data is stored in the prohibition setting memory area 19B.
[0037]
If power-on to the AM / FM broadcast receiver 1 is detected in step S11, the pre-seek operation after step S12 is executed, but even if a mode change from FM to AM is detected. Similarly, the pre-seek operation after step S12 may be executed.
[0038]
Next, an AM seek process for starting an AM broadcast seek operation after storing all spurious predicted frequencies in the AM frequency band in the prohibition setting memory area 19B in the spurious prohibition setting process will be described. FIG. 4 is a flowchart showing the processing operation of the microcomputer 20 related to the AM seek processing inside the AM / FM broadcast receiver 1 according to the present embodiment.
[0039]
The AM seek process shown in FIG. 4 is a process for avoiding an unnecessary seek operation stop by avoiding a spurious predicted frequency in the AM frequency band and receiving only a valid AM broadcast.
[0040]
In FIG. 4, when the microcomputer 20 starts a seek operation for AM broadcasting (step S21), the microcomputer 20 determines whether or not the S meter of the received frequency received by the seek exceeds a predetermined value through the effective station detection circuit 18 (step S22). .
[0041]
If the S meter of the received frequency that has received the seek exceeds a predetermined value, the microcomputer 20 determines whether or not the received frequency is within the predicted spurious frequency in the prohibition setting memory area 19B (step S23).
[0042]
When it is determined that the reception frequency at which the S meter exceeds the predetermined value is not within the predicted spurious frequency in the prohibition setting memory area 19B, the microcomputer 20 determines that the broadcast station having this reception frequency is a valid station, The seek operation is stopped and the received frequency is subjected to AM detection output through the detection circuit 16 (step S24), thereby terminating this processing operation.
[0043]
If it is determined that the received frequency determined that the S meter has exceeded the predetermined value in step S23 is within the spurious predicted frequency in the prohibited setting memory area 19B, the broadcast station of this received frequency is determined as an invalid station, Without stopping the seek operation, the next reception frequency is read from the reception frequency memory area 19A, and the seek operation to this reception frequency is started (step S25), and the process proceeds to step S22.
[0044]
If it is not determined that the S meter of the reception frequency received for seek has exceeded the predetermined value, the microcomputer 20 determines that the broadcast station of this reception frequency is an invalid station, and stops the seek operation in the reception frequency memory area 19A. Then, the next reception frequency is read out, and the process proceeds to step S25 where the seek operation to this reception frequency is started.
[0045]
According to the present embodiment, when reception of AM broadcast waves is selected, for example, when the power is turned on or when the mode is changed from FM to AM, the frequency within the AM frequency band is sequentially received, and the S at the received frequency is received. If it is determined that the meter exceeds the predetermined value, the reception frequency is stored in the reception frequency memory area 19A, a spurious prediction frequency is calculated based on the stored reception frequency, and the calculated spurious prediction frequency is calculated. Is stored in the prohibition setting memory area 19B, so that the stop of the seek operation by the spurious predicted frequency is prohibited, so that, for example, an interference station or an invalid station is detected as a valid station due to spurious interference that is likely to occur in AM broadcast radio waves. Therefore, it is possible to reliably prevent an unnecessary seek operation from being stopped due to erroneous determination.
[0046]
【The invention's effect】
According to the broadcast receiving apparatus of the present invention configured as described above, when reception of broadcast radio waves is selected, the frequency within the frequency band is sequentially received, and the received electric field strength at the received frequency exceeds a predetermined value. If it is determined that the reception frequency is stored, the spurious prediction frequency is calculated based on the stored reception frequency, and the calculated spurious prediction frequency is stored in the spurious prediction storage means. Since the stop of the seek operation by the seek function using the predicted spurious frequency as the reception frequency is prohibited, unnecessary spurious interference caused by erroneously determining, for example, an interference station or an invalid station as a valid station. The stop of the seek operation can be surely prevented.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a schematic configuration inside an AM / FM broadcast receiver according to an embodiment of a broadcast receiving apparatus of the present invention.
FIG. 2 is an explanatory diagram briefly showing a calculation result of a predicted spurious frequency according to the present embodiment.
FIG. 3 is a flowchart showing a processing operation of a microcomputer related to a spurious inhibition setting process of an AM / FM broadcast receiver according to the present embodiment.
FIG. 4 is a flowchart showing a processing operation of a microcomputer related to an AM seek process of an AM / FM broadcast receiver according to the present embodiment.
[Explanation of symbols]
1 AM / FM broadcast receiver (broadcast receiver)
18 Effective station detection circuit (reception field strength judgment means)
19A reception frequency memory area (reception frequency storage means)
19B Prohibition setting memory area (spurious prediction storage means)
20 Microcomputer (Spurious prediction calculation means, control means)

Claims (2)

A broadcast receiving apparatus having a seek function for stopping a seek operation when a frequency within a frequency band related to a broadcast radio wave is received and the received frequency of the seek is determined to be an effective station.
When reception of broadcast radio waves is selected, seek reception is sequentially performed in the frequency band through the seek function, and received electric field strength determination means for determining whether or not the received electric field strength at the received frequency exceeds a predetermined value;
When it is determined by the reception field strength determination means that the reception field strength exceeds a predetermined value, reception frequency storage means for storing the reception frequency;
Spurious prediction calculation means for calculating a spurious prediction frequency based on the reception frequency stored in the reception frequency storage means;
Spurious prediction storage means for storing the spurious prediction frequency calculated by the spurious prediction calculation means;
In the seek function, it has a control means for prohibiting stopping of the seek operation by the spurious prediction storage means stored spurious predicted frequency,
The spurious prediction calculation means stores a multiple frequency of the reception frequency stored in the reception frequency storage means, a sum frequency that is the sum of the reception frequencies stored in the reception frequency storage means, and the reception frequency storage means. A first difference frequency that is a difference between reception frequencies in the reception frequency, a second difference frequency that is a difference between the reception frequency stored in the reception frequency storage means and the multiple frequency, and a difference between the multiple frequencies. A broadcast receiving apparatus , wherein three difference frequencies are calculated as the spurious predicted frequency . The broadcast radio waves, according to claim 1 Symbol placement of the broadcast receiving apparatus is characterized in that an AM broadcast wave.

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