WO2010131389A1 - Receiver - Google Patents

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Publication number
WO2010131389A1
WO2010131389A1 PCT/JP2010/000645 JP2010000645W WO2010131389A1 WO 2010131389 A1 WO2010131389 A1 WO 2010131389A1 JP 2010000645 W JP2010000645 W JP 2010000645W WO 2010131389 A1 WO2010131389 A1 WO 2010131389A1
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Prior art keywords
signal
station
determination
output voltage
reference voltage
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PCT/JP2010/000645
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French (fr)
Japanese (ja)
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大久保学
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パナソニック株式会社
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Publication of WO2010131389A1 publication Critical patent/WO2010131389A1/en

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N5/00—Details of television systems
    • H04N5/44—Receiver circuitry for the reception of television signals according to analogue transmission standards
    • H04N5/50—Tuning indicators; Automatic tuning control
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N21/00—Selective content distribution, e.g. interactive television or video on demand [VOD]
    • H04N21/40—Client devices specifically adapted for the reception of or interaction with content, e.g. set-top-box [STB]; Operations thereof
    • H04N21/41—Structure of client; Structure of client peripherals
    • H04N21/426—Internal components of the client ; Characteristics thereof
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N21/00—Selective content distribution, e.g. interactive television or video on demand [VOD]
    • H04N21/40—Client devices specifically adapted for the reception of or interaction with content, e.g. set-top-box [STB]; Operations thereof
    • H04N21/43—Processing of content or additional data, e.g. demultiplexing additional data from a digital video stream; Elementary client operations, e.g. monitoring of home network or synchronising decoder's clock; Client middleware
    • H04N21/442—Monitoring of processes or resources, e.g. detecting the failure of a recording device, monitoring the downstream bandwidth, the number of times a movie has been viewed, the storage space available from the internal hard disk
    • H04N21/44209—Monitoring of downstream path of the transmission network originating from a server, e.g. bandwidth variations of a wireless network

Definitions

  • the present invention relates to a receiver having a station detection function for determining a reception state of a broadcast station signal.
  • FIG. 10 shows a basic configuration of a station detection circuit for obtaining a station detection function in a conventional receiver.
  • This circuit includes an S meter circuit 101 to which an input signal is input and a comparator 102 to which an S meter output signal from the S meter circuit 101 is input. A reference voltage is supplied to the comparator 102 together with the S meter output signal.
  • the output signal of the S meter circuit 101 is a voltage signal proportional to the input signal intensity at a predetermined reception frequency.
  • the comparator 102 compares the voltage of the S meter output signal with the reference voltage, and determines whether or not the input signal strength is equal to or higher than the reference voltage, that is, whether or not the input signal strength is equal to or higher than the strength defined by the reference voltage. judge. Thereby, presence / absence determination of a predetermined broadcast station signal, that is, station detection is performed, and an SD signal indicating whether or not the predetermined broadcast station signal is in a valid reception state is output.
  • the S meter circuit 101 is configured as shown in FIG. 11, for example. This circuit is composed of a plurality of peak detection circuits 111 to 114 to which input signals are inputted, and a voltage addition circuit 115 to which those outputs are inputted. The output of the voltage adding circuit 115 becomes an S meter output signal.
  • FIG. 12 shows the operation of the presence / absence determination of a broadcasting station, that is, station detection (SD signal output) by the above-described station detection circuit.
  • An S meter output signal shown in FIG. 12B is generated from the input signal shown in FIG. (B) shows the reference voltage along with the S meter output signal. The level of the S meter output signal is compared with the reference voltage, and the SD signal shown in (c) is output. That is, when the level of the S meter output signal is lower than the reference voltage, the SD signal is at the L level, and when the level of the S meter output signal exceeds the reference voltage, the SD signal becomes the H level.
  • the reference voltage in the above configuration is generally set to a very low voltage (for example, 20 dB ⁇ V or less) in order to increase the station detection sensitivity. Therefore, the problem described below is likely to occur.
  • the input signal strength to the receiver varies greatly from 0 dB ⁇ V to 120 dB ⁇ V depending on the distance between the transmitter and the receiver, the environment, and the like.
  • the S meter output voltage is stably output.
  • the input signal strength is low (for example, 20 dB ⁇ V or less)
  • the S meter output voltage becomes unstable. As a result, the SD signal output may fluctuate.
  • the SD signal output fluctuates in this way, it will interfere with the automatic station detection function of the broadcast station. For example, the automatic station detection time becomes long, or in the worst case, the broadcast station cannot be detected, and the situation is such that the search continues for the broadcast station.
  • a hysteresis function is incorporated in the comparator to reduce the flutter.
  • Patent Document 1 states that “the SD output signal is checked a plurality of times, and when the SD signal is“ valid ”more than a predetermined number of times, the frequency search mode is canceled and the frequency station is set in the receiving state”. Discloses a technique for stabilizing station detection when the electric field is unstable.
  • Patent Document 1 has a problem that the automatic station detection time is prolonged because the station detection determination is always performed for a certain time for a station that may be received.
  • an object of the present invention is to provide a receiver capable of suppressing erroneous determination of station detection of a broadcasting station due to a difference in input signal strength and the like and capable of performing automatic station detection in a short time.
  • the receiver according to the present invention has a reception function of selecting and demodulating a desired broadcast station signal from an input signal, and whether the input signal strength is an effective reception state with a predetermined frequency or higher for a reception signal of a predetermined frequency. It has a function of performing a station detection determination for detecting whether or not.
  • a receiver of the present invention includes an S meter circuit that outputs an S meter output voltage proportional to an input signal intensity of a selected reception signal of the predetermined frequency, and a plurality of S meter output voltages.
  • An SD determination circuit configured to perform the station detection determination based on whether or not the S meter output voltage is greater than or equal to the intensity defined by the reference voltage with respect to the reception signal of the predetermined frequency compared with a reference voltage;
  • the SD determination circuit outputs an SD signal indicating whether or not the reception signal of the predetermined frequency is in the effective reception state according to the state of the magnitude relationship between the S meter output voltage and the plurality of reference voltages.
  • the S meter output voltage is compared with a plurality of reference voltages, and the station detection determination is performed according to the magnitude relation state. It is possible to eliminate the determination and shorten the automatic station detection time of the broadcasting station.
  • FIG. 1 is a block diagram showing a station detection circuit included in a receiver according to Embodiment 1 of the present invention.
  • FIG. 2 is a flowchart showing an algorithm example of the SD determination circuit in the same station detection circuit.
  • FIG. 3 is a waveform diagram showing an operation when the S meter output voltage is higher than the second reference voltage in the flow of FIG.
  • FIG. 4 is a waveform diagram showing an operation when the S meter output voltage is lower than the second reference voltage and higher than the first reference voltage in the flow of FIG.
  • FIG. 5 is a block diagram showing a station detection circuit included in the receiver according to Embodiment 2 of the present invention.
  • FIG. 6 is a flowchart showing an algorithm example of the SD determination circuit in the same station detection circuit.
  • FIG. 7 is a waveform diagram showing an operation when the S meter output voltage is higher than the third reference voltage in the flow of FIG.
  • FIG. 8 is a waveform diagram showing an operation when the S meter output voltage is lower than the third reference voltage and higher than the second reference voltage in the flow of FIG.
  • FIG. 9 is a waveform diagram showing an operation when the S meter output voltage is lower than the second reference voltage and higher than the first reference voltage in the flow of FIG. 6.
  • FIG. 10 is a block diagram showing a conventional station detection circuit.
  • FIG. 11 is a block diagram illustrating an example of the S meter circuit.
  • FIG. 12 is a waveform diagram showing an example of signal processing in the conventional station detection circuit.
  • FIG. 13 is a waveform diagram showing an example of SD signal flutter.
  • the receiver of the present invention can take the following modes based on the above configuration.
  • the SD determination circuit first compares the S meter output voltage with the reference voltage V1, and then the comparison order is set so as to sequentially compare the reference voltage Vn with a lower reference voltage. In comparison with the reference voltage V1, if the S meter output voltage is smaller, a station-less SD signal indicating that the received signal of the predetermined frequency is not in a valid receiving state is output and the station detection determination is completed. To do. When the S meter output voltage is larger, the process proceeds to the comparison with the reference voltage Vn.
  • the station detection determination is completed by outputting an SD signal with a station indicating that the reception signal of the predetermined frequency is in a valid reception state, and if it is smaller than the reference voltage, the process proceeds to comparison with the next reference voltage. .
  • the comparison with the reference voltage V2 if the S meter output voltage is larger than the reference voltage V2, the station-provided SD signal is output and the station detection determination is terminated.
  • the SD signal with station or the SD signal without station is output according to the determination of the stability of the S meter output voltage in a certain determination period. The station detection determination is terminated.
  • the SD signal with the station is output, and the predetermined ratio If it is less than the above, the station-less SD signal can be output.
  • the station SD It is preferable to end the station detection determination by outputting a signal or the station-less SD signal.
  • the reference voltage Vk can be configured such that n is 2 or 3.
  • the receiver can be composed of an analog signal processing circuit or a digital signal processing circuit.
  • FIG. 1 is a block diagram showing a station detection circuit constituting the receiver in Embodiment 1 of the present invention.
  • This circuit includes an S meter circuit 1 to which an input signal is input, and an SD determination circuit 2 to which an S meter output signal from the S meter circuit 1 is input.
  • the SD determination circuit 2 is supplied with the first reference voltage Va1 and the second reference voltage Va2 (Va2> Va1) together with the S meter output signal.
  • the S meter circuit 1 outputs a voltage proportional to the input signal intensity as an S meter output signal.
  • the SD determination circuit 2 determines the presence / absence of a broadcasting station using the S meter output voltage, the first reference voltage Va1, and the second reference voltage Va2.
  • the S meter output signal is desirably a voltage proportional to the input signal intensity in terms of the system, but is not limited thereto. That is, as the S meter output signal, if a voltage reflecting the input signal intensity is output so as to increase or decrease in accordance with the increase or decrease of the input signal, the station detection operation in the present invention can be realized. is there.
  • FIG. 2 shows an example of an algorithm for the operation of the SD determination circuit 2 in the station detection circuit having the above configuration.
  • the operation of the SD determination circuit 2 will be described with reference to the algorithm of FIG.
  • the S meter output voltage is compared with Va1 (step S10).
  • the station-less SD signal is output (step S15), and the SD determination is terminated.
  • the S meter output voltage is larger than Va1 (Yes)
  • the S meter output voltage and Va2 are compared (step S11).
  • the SD signal with station is output (step S14), and the SD determination is terminated.
  • the S meter output voltage is smaller than Va2 (No)
  • the flutter determination is started (step S12).
  • the flutter determination is performed by comparing the S meter output voltage and Va1 during a predetermined determination period. This determination period can be arbitrarily set, and is a period in which the S meter output voltage and Va1 are continuously compared, and the degree of fluttering is measured for the comparison result as described below.
  • step S13 it is determined whether or not the period in which the S meter output voltage is greater than Va1 has occupied a predetermined ratio or more with respect to the determination period.
  • the period in which the S meter output voltage is greater than the first reference voltage Va1 occupies a predetermined ratio or more (Yes) it is determined that there is a station, and an SD signal with a station is output (step S14).
  • step S15 if the S meter output voltage is smaller than the first reference voltage Va1 during a predetermined ratio during the determination period, it is determined that there is no station, and a station-less SD signal is output (step S15).
  • the determination period ends. Without waiting, the SD signal with station or the SD signal without station is output, and the SD determination ends.
  • FIGS. 3 and 4 are waveform diagrams showing an operation example of the SD determination circuit 2 according to the above algorithm example.
  • the S meter output signal shown in (b) is generated from the input signal shown in (a) of FIGS. (B) also shows the first reference voltage Va1 and the second reference voltage Va2 together with the S meter output signal. The level of the S meter output signal is compared with Va1 and Va2, and the SD signal shown in (c) is output.
  • FIG. 3 shows an example in which the S meter output voltage is larger than the second reference voltage Va2.
  • the level of the S meter output signal exceeds Va2, so the SD signal immediately becomes H level.
  • FIG. 4 shows an example in which the S meter output voltage is smaller than the second reference voltage Va2 and larger than the first reference voltage Va1.
  • the S meter output signal becomes a level between Va1 and Va2, so that the flutter determination starts.
  • a period during which the S meter output voltage is greater than Va1 reaches a predetermined ratio, and an H level SD signal is output as a determination result.
  • an L level SD signal is output as a determination result. Is output.
  • FIG. 5 is a block diagram showing a station detection circuit constituting the receiver according to Embodiment 2 of the present invention.
  • the station detection circuit of this embodiment is as shown in FIGS. Further, it is configured using three reference voltages.
  • the configuration of the SD determination circuit 3 is different from that of the SD determination circuit 2 in the first embodiment, and the first reference voltage Vb1, the second reference voltage Vb2, and the third reference voltage Vb3 are supplied (Va3> Va2). > Va1).
  • the configuration of the S meter circuit 1 is the same as that of the first embodiment, and repeated description is omitted.
  • FIG. 6 shows an example of an algorithm related to the operation of the SD determination circuit 3 in the station detection circuit having the above configuration.
  • the operation of the SD determination circuit 3 will be described with reference to the algorithm of FIG.
  • the S meter output voltage is compared with Vb1 (step S20).
  • the station-less SD signal is output (step S26), and the SD determination is terminated.
  • the S meter output voltage is higher than Vb1 (Yes)
  • the S meter output voltage is compared with Vb3 (step S21).
  • step S25 When the S meter output voltage is greater than Vb3 (Yes), the SD signal with station is output (step S25), and the SD determination is terminated.
  • the S meter output voltage is smaller than Va3 (No)
  • the S meter output voltage is compared with Vb2 (step S22).
  • the SD signal with station is output (step S25), and the SD determination is terminated.
  • the S meter output voltage is smaller than Vb2 (No)
  • the flutter determination is started (step S23). As in the case of the first embodiment, the flutter determination operation is as follows.
  • step S24 it is determined whether or not the period during which the S meter output voltage is greater than Vb1 has occupied a predetermined ratio or more with respect to the determination period (step S24).
  • the period during which the S meter output voltage is greater than Va1 occupies a predetermined ratio or more (Yes) it is determined that there is a station and an SD signal with a station is output (step S25).
  • the S meter output voltage is lower than the first reference voltage Vb1 during a predetermined ratio during the determination period, it is determined that there is no station, and a station-less SD signal is output (step S26).
  • the determination period ends. Without waiting, the SD signal with station or the SD signal without station is output, and the SD determination ends.
  • FIG. 7 to 9 are waveform diagrams showing an operation example of the SD determination circuit 3 according to the above algorithm example.
  • FIG. 7 shows an example when the S meter output voltage is larger than the third reference voltage Vb3, and the operation is the same as that shown in FIG. 3 of the first embodiment.
  • FIG. 8 shows an example in which the S meter output voltage is smaller than the third reference voltage Vb3 and larger than the second reference voltage Vb2. The operation in this case is the same as that shown in FIG. 3 of the first embodiment.
  • FIG. 9 shows an example in which the S meter output voltage is smaller than the second reference voltage Vb2 and larger than the first reference voltage Vb1.
  • the operation in this case is the same as that shown in FIG. 4 of the first embodiment. That is, after the operation of the station detection circuit is started, as shown in (b), since the level of the S meter output signal is between Vb1 and Vb2, the flutter determination starts. As a result of continuing the comparison between the S meter output voltage and Vb1, a period during which the S meter output voltage is larger than Vb1 reaches a predetermined ratio, and an H level SD signal, that is, an SD signal with a station is output as a determination result.
  • SD determination circuit as described above can also be configured using four or more reference voltages.
  • the present invention can be applied not only to a receiver in which the S meter circuit and the SD determination circuit are configured by an analog signal processing circuit, but also to a receiver in which the S meter circuit and the SD determination circuit are configured from a digital signal processing circuit. it can. For example, if the input signal is an analog signal, apply to a receiver with a circuit configuration that performs signal processing with an analog circuit. If the input signal is a digital signal, apply to a receiver with a circuit configuration that performs signal processing with a digital circuit. Can do.
  • the present invention it is possible to suppress erroneous determination of station detection of a broadcasting station due to a difference in input signal strength, etc., and to perform automatic station detection in a short time. Useful for vessels.

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Abstract

Disclosed is a receiver which has a station detection determining function for detecting whether or not a reception signal of a predetermined frequency is in a valid reception state in which the input signal strength is greater than or equal to a predetermined strength. To achieve this, the receiver is provided with an S meter circuit (1) which outputs an S meter output voltage proportional to the input signal strength of a selected reception signal of a predetermined frequency, and an SD determining circuit (2) which compares the S meter output voltage with a plurality of reference voltages (V1, V2) and performs station detection determination on the reception signal of the predetermined frequency based on whether or not the S meter output voltage is greater than or equal to the strength defined by the reference voltage. The SD determining circuit is characterized in that the SD determining circuit outputs an SD signal indicating whether or not the reception signal of the predetermined frequency is in a valid reception state, based on the state of relative magnitude of the S meter output voltage to the plurality of reference voltages. The receiver suffers from less erroneous determination of detection of broadcast stations arising from differences in input signal strength, and is able to automatically perform station detection in a short period of time.

Description

受信器Receiver
　本発明は、放送局信号の受信状態を判定する局検出機能を有する受信器に関するものである。 The present invention relates to a receiver having a station detection function for determining a reception state of a broadcast station signal.
　受信器への入力信号から、所定の放送局信号の存在を検出するための局検出機能が知られている。図１０は、従来例の受信器における、局検出機能を得るための局検出回路の基本構成を示す。この回路は、入力信号が入力されるＳメーター回路１０１と、Ｓメーター回路１０１からのＳメーター出力信号が入力される比較器１０２からなる。比較器１０２には、Ｓメーター出力信号とともに基準電圧が供給される。 A station detection function for detecting the presence of a predetermined broadcast station signal from an input signal to a receiver is known. FIG. 10 shows a basic configuration of a station detection circuit for obtaining a station detection function in a conventional receiver. This circuit includes an S meter circuit 101 to which an input signal is input and a comparator 102 to which an S meter output signal from the S meter circuit 101 is input. A reference voltage is supplied to the comparator 102 together with the S meter output signal.
　Ｓメーター回路１０１の出力信号は、所定の受信周波数での入力信号強度に比例した電圧信号である。比較器１０２は、Ｓメーター出力信号の電圧と基準電圧を比較し、入力信号強度が基準電圧以上であるか否か、つまり入力信号強度が基準電圧で定義された強度以上に達しているかどうかを判定する。これにより所定の放送局信号の有無判定、すなわち局検出を行い、所定の放送局信号が有効な受信状態であるか否かを示すＳＤ信号を出力する。 The output signal of the S meter circuit 101 is a voltage signal proportional to the input signal intensity at a predetermined reception frequency. The comparator 102 compares the voltage of the S meter output signal with the reference voltage, and determines whether or not the input signal strength is equal to or higher than the reference voltage, that is, whether or not the input signal strength is equal to or higher than the strength defined by the reference voltage. judge. Thereby, presence / absence determination of a predetermined broadcast station signal, that is, station detection is performed, and an SD signal indicating whether or not the predetermined broadcast station signal is in a valid reception state is output.
　Ｓメーター回路１０１は、例えば図１１に示すように構成される。この回路は、入力信号が入力される複数のピーク検波回路１１１～１１４と、それらの出力が入力される電圧加算回路１１５から構成される。電圧加算回路１１５の出力が、Ｓメーター出力信号となる。 The S meter circuit 101 is configured as shown in FIG. 11, for example. This circuit is composed of a plurality of peak detection circuits 111 to 114 to which input signals are inputted, and a voltage addition circuit 115 to which those outputs are inputted. The output of the voltage adding circuit 115 becomes an S meter output signal.
　図１２に、上述の局検出回路による放送局の有無判定、すなわち局検出（ＳＤ信号出力）の動作を示す。図１２の（ａ）に示す入力信号から、（ｂ）に示すＳメーター出力信号が生成される。（ｂ）には、Ｓメーター出力信号とともに、基準電圧も示される。Ｓメーター出力信号のレベルが基準電圧と比較されて、（ｃ）に示すＳＤ信号が出力される。すなわち、Ｓメーター出力信号のレベルが基準電圧より低い場合は、ＳＤ信号がＬレベルであり、Ｓメーター出力信号のレベルが基準電圧を超えるとＳＤ信号がＨレベルになる。 FIG. 12 shows the operation of the presence / absence determination of a broadcasting station, that is, station detection (SD signal output) by the above-described station detection circuit. An S meter output signal shown in FIG. 12B is generated from the input signal shown in FIG. (B) shows the reference voltage along with the S meter output signal. The level of the S meter output signal is compared with the reference voltage, and the SD signal shown in (c) is output. That is, when the level of the S meter output signal is lower than the reference voltage, the SD signal is at the L level, and when the level of the S meter output signal exceeds the reference voltage, the SD signal becomes the H level.
　上記構成における基準電圧は、一般的には、局検出感度を高くするために非常に低い電圧（例えば２０ｄＢμＶ以下）に設定される。そのため、以下に説明するような問題が発生し易い。 The reference voltage in the above configuration is generally set to a very low voltage (for example, 20 dBμV or less) in order to increase the station detection sensitivity. Therefore, the problem described below is likely to occur.
　通常、受信器への入力信号強度は、送信器側と受信器側の距離、環境等の状況により、０ｄＢμＶから１２０ｄＢμＶのように大きく変化する。この入力信号強度が高いとき（例えば５０ｄＢμＶ以上）には、Ｓメーター出力電圧は安定して出力される。しかし、入力信号強度が低いとき（例えば２０ｄＢμＶ以下）には、Ｓメーター出力電圧が不安定になる。その結果として、ＳＤ信号出力にバタツキが生じることがある。 Usually, the input signal strength to the receiver varies greatly from 0 dBμV to 120 dBμV depending on the distance between the transmitter and the receiver, the environment, and the like. When the input signal strength is high (for example, 50 dBμV or more), the S meter output voltage is stably output. However, when the input signal strength is low (for example, 20 dBμV or less), the S meter output voltage becomes unstable. As a result, the SD signal output may fluctuate.
　すなわち、入力信号強度が図１３（ａ）に示すように変化するとき、（ｂ）に示すようにＳメーター出力電圧が基準電圧の近傍のレベルで変動することになる。そのため、（ｃ）に示すようにＳＤ信号がＬとＨの間で頻繁に変化する。このＳＤ信号出力のバタツキは、Ｓメーター出力電圧が基準電圧と同等程度になる入力信号強度のときにはさらにひどくなる。 That is, when the input signal intensity changes as shown in FIG. 13 (a), the S meter output voltage fluctuates at a level near the reference voltage as shown in (b). Therefore, the SD signal frequently changes between L and H as shown in (c). The fluctuation of the SD signal output is further aggravated when the input signal intensity is such that the S meter output voltage is approximately equal to the reference voltage.
　このようにＳＤ信号出力にバタツキが生じると、放送局の自動局検出機能に支障をきたす。例えば、自動局検出時間が長くなったり、最悪の場合、放送局を検出することができず、ひたすら放送局を探し続けるような状況に陥る。 If the SD signal output fluctuates in this way, it will interfere with the automatic station detection function of the broadcast station. For example, the automatic station detection time becomes long, or in the worst case, the broadcast station cannot be detected, and the situation is such that the search continues for the broadcast station.
　このような問題を解消するために、比較器にヒステリシス機能を組み込み、バタツキを軽減させるための対応がされている。 In order to solve such a problem, a hysteresis function is incorporated in the comparator to reduce the flutter.
　また特許文献１には、「ＳＤ出力信号を複数回チェックし、ＳＤ信号が所定の回数以上“有効”である場合に周波数検索モードを解除して、その周波数局を受信状態とする。」ことにより、電界が不安定なときの局検出を安定させる技術が開示されている。 Patent Document 1 states that “the SD output signal is checked a plurality of times, and when the SD signal is“ valid ”more than a predetermined number of times, the frequency search mode is canceled and the frequency station is set in the receiving state”. Discloses a technique for stabilizing station detection when the electric field is unstable.
特開平１０－３０３７７１号公報Japanese Patent Laid-Open No. 10-303771
　しかし、比較器にヒステリシス機能を組み込む対応では、ＳＤ信号出力のバタツキを十分に軽減することができていない。 However, when the hysteresis function is incorporated in the comparator, the fluctuation of the SD signal output cannot be sufficiently reduced.
　また、特許文献１の技術では、受信できる可能性がある局に対して、常に一定時間の局検出判定を行うために自動局検出時間が長期化してしまうという問題点がある。 Also, the technique of Patent Document 1 has a problem that the automatic station detection time is prolonged because the station detection determination is always performed for a certain time for a station that may be received.
　そこで本発明は、入力信号強度の違い等に起因する放送局の局検出の誤判定を抑制し、しかも短時間で自動局検出を行うことが可能な受信器を提供することを目的とする。 Therefore, an object of the present invention is to provide a receiver capable of suppressing erroneous determination of station detection of a broadcasting station due to a difference in input signal strength and the like and capable of performing automatic station detection in a short time.
　本発明の受信器は、入力信号から所望の放送局信号を選局し復調する受信機能を有するとともに、所定周波数の受信信号について、入力信号強度が所定の強度以上の有効な受信状態であるか否かを検出するための局検出判定を行う機能を備える。 The receiver according to the present invention has a reception function of selecting and demodulating a desired broadcast station signal from an input signal, and whether the input signal strength is an effective reception state with a predetermined frequency or higher for a reception signal of a predetermined frequency. It has a function of performing a station detection determination for detecting whether or not.
　上記課題を解決するために本発明の受信器は、選択された前記所定周波数の受信信号の入力信号強度に比例したＳメーター出力電圧を出力するＳメーター回路と、前記Ｓメーター出力電圧を複数の基準電圧と比較し、前記所定周波数の受信信号について、前記Ｓメーター出力電圧が前記基準電圧で定義された強度以上であるか否かに基づいて前記局検出判定を行うＳＤ判定回路とを備える。前記ＳＤ判定回路は、前記Ｓメーター出力電圧と前記複数の基準電圧との大小関係の状態に応じて、前記所定周波数の受信信号が前記有効な受信状態であるか否かを示すＳＤ信号を出力する。 In order to solve the above-described problems, a receiver of the present invention includes an S meter circuit that outputs an S meter output voltage proportional to an input signal intensity of a selected reception signal of the predetermined frequency, and a plurality of S meter output voltages. An SD determination circuit configured to perform the station detection determination based on whether or not the S meter output voltage is greater than or equal to the intensity defined by the reference voltage with respect to the reception signal of the predetermined frequency compared with a reference voltage; The SD determination circuit outputs an SD signal indicating whether or not the reception signal of the predetermined frequency is in the effective reception state according to the state of the magnitude relationship between the S meter output voltage and the plurality of reference voltages. To do.
　上記構成によれば、Ｓメーター出力電圧を複数の基準電圧と比較して、その大小関係の状態に応じて局検出判定を行うので、入力信号強度の違い等によって生じる放送局の局検出の誤判定をなくし、放送局の自動局検出時間を短くすることが可能となる。 According to the above configuration, the S meter output voltage is compared with a plurality of reference voltages, and the station detection determination is performed according to the magnitude relation state. It is possible to eliminate the determination and shorten the automatic station detection time of the broadcasting station.
図１は、本発明の実施の形態１における受信器に含まれる局検出回路を示すブロック図である。FIG. 1 is a block diagram showing a station detection circuit included in a receiver according to Embodiment 1 of the present invention. 図２は、同局検出回路におけるＳＤ判定回路のアルゴリズム例を示すフローチャートである。FIG. 2 is a flowchart showing an algorithm example of the SD determination circuit in the same station detection circuit. 図３は、図２のフローにおいてＳメーター出力電圧が第２基準電圧より高い場合の動作を示す波形図である。FIG. 3 is a waveform diagram showing an operation when the S meter output voltage is higher than the second reference voltage in the flow of FIG. 図４は、図２のフローにおいてＳメーター出力電圧が第２基準電圧より低く、第１基準電圧より高い場合の動作を示す波形図である。FIG. 4 is a waveform diagram showing an operation when the S meter output voltage is lower than the second reference voltage and higher than the first reference voltage in the flow of FIG. 図５は、本発明の実施の形態２における受信器に含まれる局検出回路を示すブロック図である。FIG. 5 is a block diagram showing a station detection circuit included in the receiver according to Embodiment 2 of the present invention. 図６は、同局検出回路におけるＳＤ判定回路のアルゴリズム例を示すフローチャートである。FIG. 6 is a flowchart showing an algorithm example of the SD determination circuit in the same station detection circuit. 図７は、図６のフローにおいてＳメーター出力電圧が第３基準電圧より高い場合の動作を示す波形図である。FIG. 7 is a waveform diagram showing an operation when the S meter output voltage is higher than the third reference voltage in the flow of FIG. 図８は、図６のフローにおいてＳメーター出力電圧が第３基準電圧より低く、第２基準電圧より高い場合の動作を示す波形図である。FIG. 8 is a waveform diagram showing an operation when the S meter output voltage is lower than the third reference voltage and higher than the second reference voltage in the flow of FIG. 図９は、図６のフローにおいてＳメーター出力電圧が第２基準電圧より低く、第１基準電圧より高い場合の動作を示す波形図である。FIG. 9 is a waveform diagram showing an operation when the S meter output voltage is lower than the second reference voltage and higher than the first reference voltage in the flow of FIG. 6. 図１０は、従来例の局検出回路を示すブロック図である。FIG. 10 is a block diagram showing a conventional station detection circuit. 図１１は、Ｓメーター回路の例を示すブロック図である。FIG. 11 is a block diagram illustrating an example of the S meter circuit. 図１２は、従来例の局検出回路における信号処理の例を示す波形図である。FIG. 12 is a waveform diagram showing an example of signal processing in the conventional station detection circuit. 図１３は、ＳＤ信号のバタツキの例を示す波形図である。FIG. 13 is a waveform diagram showing an example of SD signal flutter.
　本発明の受信器は、上記構成を基本として、以下のような態様をとることができる。 The receiver of the present invention can take the following modes based on the above configuration.
　すなわち、前記複数の基準電圧をＶｋ（ｋは１～ｎで、ｎは２以上の整数）と記述し、Ｖ（ｋ－１）＜Ｖｋと定義したとき、以下の構成とすることができる。すなわち、前記ＳＤ判定回路は、最初に、前記Ｓメーター出力電圧と基準電圧Ｖ１の比較を行い、その後、基準電圧Ｖｎから順次低い基準電圧との比較を行うように比較順序が設定される。前記基準電圧Ｖ１との比較では、前記Ｓメーター出力電圧の方が小さい場合は、前記所定周波数の受信信号が有効な受信状態ではないことを示す局なしＳＤ信号を出力して局検出判定を終了する。前記Ｓメーター出力電圧の方が大きい場合は、基準電圧Ｖｎとの比較に移行し、Ｖｎ～Ｖ３までの基準電圧との比較では、前記Ｓメーター出力電圧が、当該基準電圧よりも大きい場合は、前記所定周波数の受信信号が有効な受信状態であることを示す局ありＳＤ信号を出力して局検出判定を終了し、当該基準電圧よりも小さい場合は、次の基準電圧との比較に移行する。基準電圧Ｖ２との比較に至ったときの動作では、前記Ｓメーター出力電圧が基準電圧Ｖ２よりも大きい場合は、前記局ありＳＤ信号を出力して局検出判定を終了する。前記Ｓメーター出力電圧が基準電圧Ｖ２よりも小さい場合は、一定の判定期間における、前記Ｓメーター出力電圧の安定度の判定に応じて、前記局ありＳＤ信号または前記局なしＳＤ信号を出力して局検出判定を終了する。 That is, when the plurality of reference voltages are described as Vk (k is 1 to n, n is an integer of 2 or more) and defined as V (k−1) <Vk, the following configuration can be adopted. That is, the SD determination circuit first compares the S meter output voltage with the reference voltage V1, and then the comparison order is set so as to sequentially compare the reference voltage Vn with a lower reference voltage. In comparison with the reference voltage V1, if the S meter output voltage is smaller, a station-less SD signal indicating that the received signal of the predetermined frequency is not in a valid receiving state is output and the station detection determination is completed. To do. When the S meter output voltage is larger, the process proceeds to the comparison with the reference voltage Vn. When the S meter output voltage is larger than the reference voltage in the comparison with the reference voltages from Vn to V3, The station detection determination is completed by outputting an SD signal with a station indicating that the reception signal of the predetermined frequency is in a valid reception state, and if it is smaller than the reference voltage, the process proceeds to comparison with the next reference voltage. . In the operation when the comparison with the reference voltage V2 is reached, if the S meter output voltage is larger than the reference voltage V2, the station-provided SD signal is output and the station detection determination is terminated. When the S meter output voltage is smaller than the reference voltage V2, the SD signal with station or the SD signal without station is output according to the determination of the stability of the S meter output voltage in a certain determination period. The station detection determination is terminated.
　また、前記判定期間には、前記Ｓメーター出力電圧が基準電圧Ｖ１よりも大きい期間が、前記判定期間の長さに対して所定割合以上となったときには前記局ありＳＤ信号を出力し、所定割合に満たなかったときには前記局なしＳＤ信号を出力する構成とすることができる。 In the determination period, when the period in which the S meter output voltage is greater than the reference voltage V1 is equal to or greater than a predetermined ratio with respect to the length of the determination period, the SD signal with the station is output, and the predetermined ratio If it is less than the above, the station-less SD signal can be output.
　また、前記判定期間終了前に、Ｓメーター出力電圧が基準電圧Ｖ１よりも大きい状態または小さい状態の期間が、前記所定割合に達した場合には、判定期間終了を待たずに、前記局ありＳＤ信号、または前記局なしＳＤ信号を出力して局検出判定を終了することが好ましい。 In addition, if the period when the S meter output voltage is larger or smaller than the reference voltage V1 reaches the predetermined ratio before the end of the determination period, the station SD It is preferable to end the station detection determination by outputting a signal or the station-less SD signal.
　また、前記基準電圧Ｖｋのｎが２または３である構成とすることができる。 Further, the reference voltage Vk can be configured such that n is 2 or 3.
　また、受信器は、アナログ信号処理回路またはデジタル信号処理回路で構成することができる。 Also, the receiver can be composed of an analog signal processing circuit or a digital signal processing circuit.
　以下、本発明の実施形態について図面を参照しながら、より具体的に説明する。 Hereinafter, embodiments of the present invention will be described more specifically with reference to the drawings.
　（実施の形態１）
　図１は、本発明の実施の形態１における受信器を構成する局検出回路を示すブロック図である。この回路は、入力信号が入力されるＳメーター回路１と、Ｓメーター回路１からのＳメーター出力信号が入力されるＳＤ判定回路２からなる。ＳＤ判定回路２には、Ｓメーター出力信号とともに、第１基準電圧Ｖａ１、第２基準電圧Ｖａ２（Ｖａ２＞Ｖａ１）が供給される。 (Embodiment 1)
FIG. 1 is a block diagram showing a station detection circuit constituting the receiver in Embodiment 1 of the present invention. This circuit includes an S meter circuit 1 to which an input signal is input, and an SD determination circuit 2 to which an S meter output signal from the S meter circuit 1 is input. The SD determination circuit 2 is supplied with the first reference voltage Va1 and the second reference voltage Va2 (Va2> Va1) together with the S meter output signal.
　Ｓメーター回路１は、入力信号強度に比例した電圧をＳメーター出力信号として出力する。ＳＤ判定回路２は、このＳメーター出力電圧、第１基準電圧Ｖａ１、第２基準電圧Ｖａ２を用いて、放送局有無の判定を行う。なお、Ｓメーター出力信号は、システム的には入力信号強度に比例した電圧であることが望ましいが、これに限られるものではない。すなわち、Ｓメーター出力信号としては、入力信号の増減に対応して増減する関係を有するように、入力信号強度が反映された電圧が出力されれば、本発明における局検出の動作を実現可能である。 The S meter circuit 1 outputs a voltage proportional to the input signal intensity as an S meter output signal. The SD determination circuit 2 determines the presence / absence of a broadcasting station using the S meter output voltage, the first reference voltage Va1, and the second reference voltage Va2. The S meter output signal is desirably a voltage proportional to the input signal intensity in terms of the system, but is not limited thereto. That is, as the S meter output signal, if a voltage reflecting the input signal intensity is output so as to increase or decrease in accordance with the increase or decrease of the input signal, the station detection operation in the present invention can be realized. is there.
　上記構成の局検出回路におけるＳＤ判定回路２の動作のアルゴリズムの例を、図２に示す。以下、図２のアルゴリズムを参照して、ＳＤ判定回路２の動作を説明する。 FIG. 2 shows an example of an algorithm for the operation of the SD determination circuit 2 in the station detection circuit having the above configuration. Hereinafter, the operation of the SD determination circuit 2 will be described with reference to the algorithm of FIG.
　局検出回路の動作がスタートすると、最初に、Ｓメーター出力電圧とＶａ１を比較する（ステップＳ１０）。Ｓメーター出力電圧がＶａ１より小さいとき（Ｎｏ）には、局なしＳＤ信号を出力して（ステップＳ１５）、ＳＤ判定を終了する。Ｓメーター出力電圧がＶａ１より大きいとき（Ｙｅｓ）には、Ｓメーター出力電圧とＶａ２を比較する（ステップＳ１１）。 When the operation of the station detection circuit starts, first, the S meter output voltage is compared with Va1 (step S10). When the S meter output voltage is smaller than Va1 (No), the station-less SD signal is output (step S15), and the SD determination is terminated. When the S meter output voltage is larger than Va1 (Yes), the S meter output voltage and Va2 are compared (step S11).
　Ｓメーター出力電圧がＶａ２より大きいときには（Ｙｅｓ）、局ありＳＤ信号を出力して（ステップＳ１４）、ＳＤ判定を終了する。Ｓメーター出力電圧がＶａ２より小さいとき（Ｎｏ）には、バタツキ判定をスタートさせる（ステップＳ１２）。バタツキ判定は、Ｓメーター出力電圧とＶａ１を一定の判定期間中比較することにより行なう。この判定期間は、任意に設定可能であり、Ｓメーター出力電圧とＶａ１を比較し続け、その比較結果について、下記のようにバタツキの程度を測定する期間である。 When the S meter output voltage is higher than Va2 (Yes), the SD signal with station is output (step S14), and the SD determination is terminated. When the S meter output voltage is smaller than Va2 (No), the flutter determination is started (step S12). The flutter determination is performed by comparing the S meter output voltage and Va1 during a predetermined determination period. This determination period can be arbitrarily set, and is a period in which the S meter output voltage and Va1 are continuously compared, and the degree of fluttering is measured for the comparison result as described below.
　バタツキ判定により、Ｓメーター出力電圧がＶａ１より大きい期間が、上記判定期間に対して所定割合以上を占めたか否かが判定される（ステップＳ１３）。Ｓメーター出力電圧が第１基準電圧Ｖａ１より大きい期間が、所定割合以上を占めた場合（Ｙｅｓ）は、局ありと判定し、局ありＳＤ信号を出力する（ステップＳ１４）。逆に、この判定期間中の所定割合の期間、Ｓメーター出力電圧が第１基準電圧Ｖａ１より小さい場合には、局なしと判定し、局なしＳＤ信号を出力する（ステップＳ１５）。 By the flutter determination, it is determined whether or not the period in which the S meter output voltage is greater than Va1 has occupied a predetermined ratio or more with respect to the determination period (step S13). When the period in which the S meter output voltage is greater than the first reference voltage Va1 occupies a predetermined ratio or more (Yes), it is determined that there is a station, and an SD signal with a station is output (step S14). Conversely, if the S meter output voltage is smaller than the first reference voltage Va1 during a predetermined ratio during the determination period, it is determined that there is no station, and a station-less SD signal is output (step S15).
　このとき、図示しないが、一定の判定期間終了前に、Ｓメーター出力電圧がＶａ１よりも大きい状態または小さい状態の期間が、判定期間に対して所定割合に達した場合には、判定期間終了を待たずに、局ありＳＤ信号もしくは局なしＳＤ信号を出力して、ＳＤ判定を終了する。 At this time, although not shown, if the period when the S meter output voltage is larger or smaller than Va1 reaches a predetermined ratio with respect to the determination period before the end of the certain determination period, the determination period ends. Without waiting, the SD signal with station or the SD signal without station is output, and the SD determination ends.
　図３及び図４は、上記アルゴリズム例による、ＳＤ判定回路２の動作例を示す波形図である。図１２に示した従来例の場合と同様、図３及び図４の（ａ）に示す入力信号から、（ｂ）に示すＳメーター出力信号が生成される。（ｂ）には、Ｓメーター出力信号とともに、第１基準電圧Ｖａ１及び第２基準電圧Ｖａ２も示される。Ｓメーター出力信号のレベルがＶａ１、Ｖａ２と比較されて、（ｃ）に示すＳＤ信号が出力される。 3 and 4 are waveform diagrams showing an operation example of the SD determination circuit 2 according to the above algorithm example. As in the case of the conventional example shown in FIG. 12, the S meter output signal shown in (b) is generated from the input signal shown in (a) of FIGS. (B) also shows the first reference voltage Va1 and the second reference voltage Va2 together with the S meter output signal. The level of the S meter output signal is compared with Va1 and Va2, and the SD signal shown in (c) is output.
　図３は、Ｓメーター出力電圧が第２基準電圧Ｖａ２より大きい場合の例を示す。この場合、局検出回路の動作がスタートした後、（ｂ）に示すように、Ｓメーター出力信号のレベルがＶａ２を超えるので、直ちにＳＤ信号がＨレベルになる。 FIG. 3 shows an example in which the S meter output voltage is larger than the second reference voltage Va2. In this case, after the operation of the station detection circuit is started, as shown in (b), the level of the S meter output signal exceeds Va2, so the SD signal immediately becomes H level.
　図４は、Ｓメーター出力電圧が第２基準電圧Ｖａ２より小さく、第１基準電圧Ｖａ１より大きい場合の例を示す。局検出回路の動作がスタートした後、（ｂ）に示すように、Ｓメーター出力信号がＶａ１とＶａ２の間のレベルになるので、バタツキ判定がスタートする。Ｓメーター出力電圧とＶａ１の比較が継続された結果、Ｓメーター出力電圧がＶａ１より大きい期間が所定割合に達し、判定結果としてＨレベルのＳＤ信号が出力される。一方、（ｂ）の図示とは異なり、所定の判定期間が経過した時点で、Ｓメーター出力電圧がＶａ１より大きい期間が所定割合に達していなかった場合は、判定結果としてＬレベルのＳＤ信号が出力される。 FIG. 4 shows an example in which the S meter output voltage is smaller than the second reference voltage Va2 and larger than the first reference voltage Va1. After the operation of the station detection circuit is started, as shown in (b), the S meter output signal becomes a level between Va1 and Va2, so that the flutter determination starts. As a result of continuing comparison between the S meter output voltage and Va1, a period during which the S meter output voltage is greater than Va1 reaches a predetermined ratio, and an H level SD signal is output as a determination result. On the other hand, unlike the illustration of (b), when a predetermined determination period has elapsed and a period in which the S meter output voltage is greater than Va1 has not reached a predetermined ratio, an L level SD signal is output as a determination result. Is output.
　（実施の形態２）
　図５は、本発明の実施の形態２における受信器を構成する局検出回路を示すブロック図である。図１及び図２に示した実施の形態１では、２つの基準電圧を用いて構成した例を示したのに対して、本実施の形態の局検出回路は、図５及び図６に示すように、３つの基準電圧を用いて構成される。 (Embodiment 2)
FIG. 5 is a block diagram showing a station detection circuit constituting the receiver according to Embodiment 2 of the present invention. In the first embodiment shown in FIGS. 1 and 2, an example in which two reference voltages are used is shown. On the other hand, the station detection circuit of this embodiment is as shown in FIGS. Further, it is configured using three reference voltages.
　従って、ＳＤ判定回路３の構成が、実施の形態１におけるＳＤ判定回路２と相違し、また、第１基準電圧Ｖｂ１、第２基準電圧Ｖｂ２及び第３基準電圧Ｖｂ３が供給される（Ｖａ３＞Ｖａ２＞Ｖａ１）。Ｓメーター回路１の構成は実施の形態１と同様であり、説明の繰り返しを省略する。 Therefore, the configuration of the SD determination circuit 3 is different from that of the SD determination circuit 2 in the first embodiment, and the first reference voltage Vb1, the second reference voltage Vb2, and the third reference voltage Vb3 are supplied (Va3> Va2). > Va1). The configuration of the S meter circuit 1 is the same as that of the first embodiment, and repeated description is omitted.
　上記構成の局検出回路におけるＳＤ判定回路３の動作に関するアルゴリズムの例を、図６に示す。以下、図６のアルゴリズムを参照して、ＳＤ判定回路３の動作を説明する。 FIG. 6 shows an example of an algorithm related to the operation of the SD determination circuit 3 in the station detection circuit having the above configuration. Hereinafter, the operation of the SD determination circuit 3 will be described with reference to the algorithm of FIG.
　局検出回路の動作がスタートすると、最初に、Ｓメーター出力電圧とＶｂ１を比較する（ステップＳ２０）。Ｓメーター出力電圧がＶｂ１より小さいとき（Ｎｏ）には、局なしＳＤ信号を出力して（ステップＳ２６）、ＳＤ判定を終了する。Ｓメーター出力電圧がＶｂ１より大きいとき（Ｙｅｓ）には、Ｓメーター出力電圧とＶｂ３を比較する（ステップＳ２１）。 When the operation of the station detection circuit starts, first, the S meter output voltage is compared with Vb1 (step S20). When the S meter output voltage is smaller than Vb1 (No), the station-less SD signal is output (step S26), and the SD determination is terminated. When the S meter output voltage is higher than Vb1 (Yes), the S meter output voltage is compared with Vb3 (step S21).
　Ｓメーター出力電圧がＶｂ３より大きいときには（Ｙｅｓ）、局ありＳＤ信号を出力して（ステップＳ２５）、ＳＤ判定を終了する。Ｓメーター出力電圧がＶａ３より小さいとき（Ｎｏ）には、Ｓメーター出力電圧とＶｂ２を比較する（ステップＳ２２）。 When the S meter output voltage is greater than Vb3 (Yes), the SD signal with station is output (step S25), and the SD determination is terminated. When the S meter output voltage is smaller than Va3 (No), the S meter output voltage is compared with Vb2 (step S22).
　Ｓメーター出力電圧がＶｂ２より大きいときには（Ｙｅｓ）、局ありＳＤ信号を出力して（ステップＳ２５）、ＳＤ判定を終了する。Ｓメーター出力電圧がＶｂ２より小さいとき（Ｎｏ）には、バタツキ判定をスタートさせる（ステップＳ２３）。バタツキ判定の動作は、実施の形態１の場合と同様、以下のとおりである。 When the S meter output voltage is greater than Vb2 (Yes), the SD signal with station is output (step S25), and the SD determination is terminated. When the S meter output voltage is smaller than Vb2 (No), the flutter determination is started (step S23). As in the case of the first embodiment, the flutter determination operation is as follows.
　バタツキ判定により、Ｓメーター出力電圧がＶｂ１より大きい期間が、判定期間に対して所定割合以上を占めたか否かが判定される（ステップＳ２４）。Ｓメーター出力電圧がＶａ１より大きい期間が、所定割合以上を占めた場合（Ｙｅｓ）は、局ありと判定し、局ありＳＤ信号を出力する（ステップＳ２５）。逆に、この判定期間中の所定割合の期間、Ｓメーター出力電圧が第１基準電圧Ｖｂ１より小さい場合には、局なしと判定し、局なしＳＤ信号を出力する（ステップＳ２６）。 By the flutter determination, it is determined whether or not the period during which the S meter output voltage is greater than Vb1 has occupied a predetermined ratio or more with respect to the determination period (step S24). When the period during which the S meter output voltage is greater than Va1 occupies a predetermined ratio or more (Yes), it is determined that there is a station and an SD signal with a station is output (step S25). Conversely, if the S meter output voltage is lower than the first reference voltage Vb1 during a predetermined ratio during the determination period, it is determined that there is no station, and a station-less SD signal is output (step S26).
　このとき、図示しないが、一定の判定期間終了前に、Ｓメーター出力電圧がＶｂ１よりも大きい状態または小さい状態の期間が、一定の判定期間に対する所定割合に達した場合には、判定期間終了を待たずに、局ありＳＤ信号もしくは局なしＳＤ信号を出力して、ＳＤ判定を終了する。 At this time, although not shown, if the period when the S meter output voltage is higher or lower than Vb1 reaches a predetermined ratio with respect to the predetermined determination period before the end of the predetermined determination period, the determination period ends. Without waiting, the SD signal with station or the SD signal without station is output, and the SD determination ends.
　このように、基準電圧を追加して、Ｓメーター出力電圧との比較処理を増やすことにより、一定期間の判定処理を行うかどうかの判定が追加されるので、結果として、局検出時間を短縮することができる。 In this way, by adding the reference voltage and increasing the comparison process with the S meter output voltage, the determination as to whether or not to perform the determination process for a certain period is added, and as a result, the station detection time is shortened. be able to.
　図７～図９は、上記アルゴリズム例による、ＳＤ判定回路３の動作例を示す波形図である。図７はＳメーター出力電圧が第３基準電圧Ｖｂ３より大きい場合の例を示し、動作は実施の形態１の図３に示した場合と同様である。図８は、Ｓメーター出力電圧が第３基準電圧Ｖｂ３より小さく、第２基準電圧Ｖｂ２より大きい場合の例を示す。この場合の動作も、実施の形態１の図３に示した場合と同様である。 7 to 9 are waveform diagrams showing an operation example of the SD determination circuit 3 according to the above algorithm example. FIG. 7 shows an example when the S meter output voltage is larger than the third reference voltage Vb3, and the operation is the same as that shown in FIG. 3 of the first embodiment. FIG. 8 shows an example in which the S meter output voltage is smaller than the third reference voltage Vb3 and larger than the second reference voltage Vb2. The operation in this case is the same as that shown in FIG. 3 of the first embodiment.
　図９は、Ｓメーター出力電圧が第２基準電圧Ｖｂ２より小さく、第１基準電圧Ｖｂ１より大きい場合の例を示す。この場合の動作は、実施の形態１の図４に示した場合と同様である。すなわち、局検出回路の動作がスタートした後、（ｂ）に示すように、Ｓメーター出力信号のレベルがＶｂ１とＶｂ２の間になるので、バタツキ判定がスタートする。Ｓメーター出力電圧とＶｂ１の比較が継続された結果、Ｓメーター出力電圧がＶｂ１より大きい期間が所定割合に達し、判定結果としてＨレベルのＳＤ信号、すなわち局ありＳＤ信号が出力される。一方、（ｂ）の図示とは異なり、所定の判定期間が経過した時点で、Ｓメーター出力電圧がＶｂ１より大きい期間が所定割合に達していなかった場合は、判定結果としてＬレベルのＳＤ信号、すなわち局なしＳＤ信号が出力される。 FIG. 9 shows an example in which the S meter output voltage is smaller than the second reference voltage Vb2 and larger than the first reference voltage Vb1. The operation in this case is the same as that shown in FIG. 4 of the first embodiment. That is, after the operation of the station detection circuit is started, as shown in (b), since the level of the S meter output signal is between Vb1 and Vb2, the flutter determination starts. As a result of continuing the comparison between the S meter output voltage and Vb1, a period during which the S meter output voltage is larger than Vb1 reaches a predetermined ratio, and an H level SD signal, that is, an SD signal with a station is output as a determination result. On the other hand, unlike the illustration of (b), when a predetermined determination period has elapsed and a period in which the S meter output voltage is greater than Vb1 has not reached a predetermined ratio, an SD signal of L level as a determination result, That is, a stationless SD signal is output.
　なお、以上のようなＳＤ判定回路を、４つ以上の基準電圧を用いて構成することも可能である。 Note that the SD determination circuit as described above can also be configured using four or more reference voltages.
　本発明は、Ｓメーター回路及びＳＤ判定回路がアナログ信号処理回路によって構成された受信器のみならず、Ｓメーター回路及びＳＤ判定回路がデジタル信号処理回路で構成された受信器にも適用することができる。例えば、入力信号がアナログ信号の場合、アナログ回路で信号処理を行う回路構成の受信器に適用し、入力信号がデジタル信号の場合、デジタル回路で信号処理を行う回路構成の受信器に適用することができる。 The present invention can be applied not only to a receiver in which the S meter circuit and the SD determination circuit are configured by an analog signal processing circuit, but also to a receiver in which the S meter circuit and the SD determination circuit are configured from a digital signal processing circuit. it can. For example, if the input signal is an analog signal, apply to a receiver with a circuit configuration that performs signal processing with an analog circuit. If the input signal is a digital signal, apply to a receiver with a circuit configuration that performs signal processing with a digital circuit. Can do.
　本発明によれば、入力信号強度の違い等に起因する放送局の局検出の誤判定を抑制し、しかも短時間で自動局検出を行うことが可能であり、種々の放送受信器、無線受信器に有用である。 According to the present invention, it is possible to suppress erroneous determination of station detection of a broadcasting station due to a difference in input signal strength, etc., and to perform automatic station detection in a short time. Useful for vessels.
１、１０１　Ｓメーター回路
２、３　ＳＤ判定回路
１０２　比較器
１１１，１１２，１１３，１１４　ピーク検波回路
１１５　電圧加算回路 DESCRIPTION OF SYMBOLS 1, 101 S meter circuit 2, 3 SD determination circuit 102 Comparator 111,112,113,114 Peak detection circuit 115 Voltage addition circuit

Claims (7)

  1. 　入力信号から所望の放送局信号を選局し復調する受信機能を有するとともに、所定周波数の受信信号について、入力信号強度が所定の強度以上の有効な受信状態であるか否かを検出するための局検出判定を行う機能を備えた受信器において、
    　選択された前記所定周波数の受信信号の入力信号強度に比例したＳメーター出力電圧を出力するＳメーター回路と、
    　前記Ｓメーター出力電圧を複数の基準電圧と比較し、前記所定周波数の受信信号について、前記Ｓメーター出力電圧が前記基準電圧で定義された強度以上であるか否かに基づいて前記局検出判定を行うＳＤ判定回路とを備え、
    　前記ＳＤ判定回路は、前記Ｓメーター出力電圧と前記複数の基準電圧との大小関係の状態に応じて、前記所定周波数の受信信号が前記有効な受信状態であるか否かを示すＳＤ信号を出力することを特徴とする受信器。     It has a reception function for selecting and demodulating a desired broadcast station signal from the input signal, and for detecting whether or not the input signal strength is an effective reception state of a predetermined strength or higher with respect to the reception signal of the predetermined frequency. In the receiver with the function to perform station detection determination,
    An S meter circuit that outputs an S meter output voltage proportional to the input signal strength of the selected reception signal of the predetermined frequency;
    The S meter output voltage is compared with a plurality of reference voltages, and the station detection determination is performed based on whether or not the S meter output voltage is greater than or equal to the intensity defined by the reference voltage for the reception signal of the predetermined frequency. An SD determination circuit to perform,
    The SD determination circuit outputs an SD signal indicating whether or not the reception signal of the predetermined frequency is in the effective reception state according to the state of the magnitude relationship between the S meter output voltage and the plurality of reference voltages. A receiver characterized by:
  2. 　前記複数の基準電圧をＶｋ（ｋは１～ｎで、ｎは２以上の整数）と記述し、Ｖ（ｋ－１）＜Ｖｋと定義したとき、
    　前記ＳＤ判定回路は、最初に、前記Ｓメーター出力電圧と基準電圧Ｖ１の比較を行い、その後、基準電圧Ｖｎから順次低い基準電圧との比較を行うように比較順序が設定され、
    　前記基準電圧Ｖ１との比較では、前記Ｓメーター出力電圧の方が小さい場合は、前記所定周波数の受信信号が有効な受信状態ではないことを示す局なしＳＤ信号を出力して局検出判定を終了し、前記Ｓメーター出力電圧の方が大きい場合は、基準電圧Ｖｎとの比較に移行し、
    　Ｖｎ～Ｖ３までの基準電圧との比較では、前記Ｓメーター出力電圧が、当該基準電圧よりも大きい場合は、前記所定周波数の受信信号が有効な受信状態であることを示す局ありＳＤ信号を出力して局検出判定を終了し、当該基準電圧よりも小さい場合は、次の基準電圧との比較に移行し、
    　基準電圧Ｖ２との比較に至ったときの動作では、前記Ｓメーター出力電圧が基準電圧Ｖ２よりも大きい場合は、前記局ありＳＤ信号を出力して局検出判定を終了し、前記Ｓメーター出力電圧が基準電圧Ｖ２よりも小さい場合は、一定の判定期間における、前記Ｓメーター出力電圧の安定度の判定に応じて、前記局ありＳＤ信号または前記局なしＳＤ信号を出力して局検出判定を終了する請求項１記載の受信器。     When the plurality of reference voltages are described as Vk (k is 1 to n, n is an integer of 2 or more) and defined as V (k−1) <Vk,
    The SD determination circuit first compares the S meter output voltage with a reference voltage V1, and then sets a comparison order so as to sequentially compare with a reference voltage that is lower than the reference voltage Vn.
    In comparison with the reference voltage V1, if the S meter output voltage is smaller, a station-less SD signal indicating that the received signal of the predetermined frequency is not in a valid receiving state is output and the station detection determination is completed. If the S meter output voltage is larger, the process proceeds to comparison with the reference voltage Vn.
    In comparison with the reference voltages from Vn to V3, if the S meter output voltage is larger than the reference voltage, an SD signal with a station indicating that the reception signal of the predetermined frequency is in a valid reception state is output. Then, the station detection determination is finished, and if it is smaller than the reference voltage, the process proceeds to comparison with the next reference voltage,
    In the operation when the comparison with the reference voltage V2 is reached, if the S meter output voltage is greater than the reference voltage V2, the station SD determination is completed by outputting the SD signal with the station, and the S meter output voltage. Is smaller than the reference voltage V2, the station detection determination is completed by outputting the SD signal with station or the SD signal without station according to the determination of the stability of the S meter output voltage in a certain determination period. The receiver according to claim 1.
  3. 　前記判定期間には、前記Ｓメーター出力電圧が基準電圧Ｖ１よりも大きい期間が、前記判定期間の長さに対して所定割合以上となったときには前記局ありＳＤ信号を出力し、所定割合に満たなかったときには前記局なしＳＤ信号を出力する請求項２記載の受信器。 In the determination period, when the period in which the S meter output voltage is larger than the reference voltage V1 is equal to or greater than a predetermined ratio with respect to the length of the determination period, the SD signal with the station is output and the predetermined ratio is satisfied. 3. The receiver according to claim 2, wherein when there is no station, the station-less SD signal is output.
  4. 　前記判定期間終了前に、Ｓメーター出力電圧が基準電圧Ｖ１よりも大きい状態または小さい状態の期間が、前記所定割合に達した場合には、判定期間終了を待たずに、前記局ありＳＤ信号または前記局なしＳＤ信号を出力して局検出判定を終了する請求項１～３のいずれか１項記載の受信器。 If the period during which the S meter output voltage is larger or smaller than the reference voltage V1 reaches the predetermined ratio before the determination period ends, the station SD signal or The receiver according to any one of claims 1 to 3, wherein the station detection determination is terminated by outputting the station-less SD signal.
  5. 　前記基準電圧Ｖｋのｎが２または３である請求項１～４のいずれか１項記載の受信器。 The receiver according to any one of claims 1 to 4, wherein n of the reference voltage Vk is 2 or 3.
  6. 　アナログ信号処理回路で構成された１～５のいずれか１項記載の受信器。 The receiver according to any one of 1 to 5, which is configured by an analog signal processing circuit.
  7. 　デジタル信号処理回路で構成された１～５のいずれか１項記載の受信器。 6. The receiver according to any one of 1 to 5, comprising a digital signal processing circuit.
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Cited By (1)

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Publication number Priority date Publication date Assignee Title
JP2019208160A (en) * 2018-05-30 2019-12-05 クラリオン株式会社 Broadcast receiver

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JPH10303771A (en) * 1997-04-30 1998-11-13 Mitsubishi Electric Corp Receiver
JP2007274072A (en) * 2006-03-30 2007-10-18 Matsushita Electric Ind Co Ltd Digital broadcast receiver
JP2008306687A (en) * 2007-06-11 2008-12-18 Toshiba Corp Apparatus and method for transmitting video image

Patent Citations (3)

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Publication number Priority date Publication date Assignee Title
JPH10303771A (en) * 1997-04-30 1998-11-13 Mitsubishi Electric Corp Receiver
JP2007274072A (en) * 2006-03-30 2007-10-18 Matsushita Electric Ind Co Ltd Digital broadcast receiver
JP2008306687A (en) * 2007-06-11 2008-12-18 Toshiba Corp Apparatus and method for transmitting video image

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2019208160A (en) * 2018-05-30 2019-12-05 クラリオン株式会社 Broadcast receiver
JP7000252B2 (en) 2018-05-30 2022-01-19 フォルシアクラリオン・エレクトロニクス株式会社 Broadcast receiver

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