JP2006025136A - Receiver - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a receiver which has simple constitution and nonetheless can select a desired wave to thereby perform an excellent receiving operation. <P>SOLUTION: A receiver 10 is used for a transmission system equipped with a plurality of transmitting stations which transmit signal waves differing in frequency and having the same contents, and selectively receives and outputs one of the signal waves transmitted from the plurality of transmitting stations as a desired wave. A microcomputer 12 judges the reception quality of the signal wave being received and further judges whether the signal wave being received is disturbed by an adjacent disturbance wave when it is judged that the reception quality is lower than a predetermined threshold level. Then the microcomputer once judging that the signal wave is disturbed selects a transmitting station which sends the signal wave that is other than the signal wave being received and is not disturbed by adjacent disturbance waves. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a receiving apparatus that automatically selects one of a plurality of transmitting stations that transmit signal waves having the same content as a receiving station and receives the signal waves from the receiving station.

  2. Description of the Related Art Conventionally, as a receiving apparatus, a receiving apparatus that selects one of a plurality of transmitting stations that transmit signal waves having the same contents as a receiving station and receives a signal wave from the receiving station is known. For example, digital data (for example, broadcast information of each transmitting station) is superimposed on an FM broadcast signal and sent as a multiplexed signal, and the receiving device demodulates the multiplexed signal and automatically selects a receiving station based on the digital data. It is done to bureau.

  As such a multiplex broadcasting system, for example, there is an RDS (Radio Data System: Radio Data System). In the RDS, each FM transmitting station (FM broadcasting station) is superimposed on an FM broadcasting signal to broadcast a program having the same content. Is transmitted as digital data (RDS data).

  In the in-vehicle receiving apparatus, the receiving station is selected as the vehicle moves. At this time, the received electric field strength of the FM broadcast signal from the receiving station is measured, and the received electric field strength is a predetermined threshold value. When the level is less than the level, the above-described AF list is referred to automatically search for a receiving station having a high received electric field strength (a receiving station that transmits an FM broadcast signal having the same content), and control for receiving switching to the receiving station is performed. I am doing so.

  By the way, the FM broadcast signal may be disturbed from a band adjacent to the FM broadcast signal (hereinafter referred to as an adjacent disturbing wave), and if there is an adjacent disturbing wave, the received electric field strength with respect to the FM broadcast signal being received. However, the reception switching is not performed even though the FM broadcast signal cannot be received and demodulated satisfactorily.

  In other words, when the reception state of the FM broadcast signal being received deteriorates according to the movement of the vehicle, the transmission station that transmits the same broadcast program with the good reception state is automatically selected as the reception station and the reception is switched. However, there are cases where reception switching with adjacent interference waves is not performed.

  In order to prevent such a problem, the received electric field strength and the adjacent interference level (including the multipath level) are measured, and the quality determination of the RDS data is performed according to the received electric field strength and the adjacent interference level. If the received electric field strength is below a predetermined level and the adjacent interference level is above a predetermined level, it is determined that the quality of the RDS data has deteriorated and reception switching (automatic tracking control) is performed ( For example, see Patent Document 1).

  Furthermore, since reception switching is performed in consideration of adjacent interfering waves, the reception field strength of a plurality of alternative frequencies of the transmitting station is checked at regular time intervals. There is one in which adjacent interference noise is detected from a signal, and when the adjacent interference noise is detected, the reception field strength threshold of the receiving station is lowered to check the reception field strength of the alternative frequency (for example, see Patent Document 2). ).

JP-A-4-329018 (pages 3 to 4, FIGS. 1 to 2) JP-A-8-335858 (Pages 3 to 5, FIGS. 1 to 8)

  However, since the conventional receiver is configured as described above, that is, the reception field strength and the adjacent interference level are measured, and the reception quality is determined based on the results. After that, it is necessary to determine whether or not a good reception state can be obtained by measuring the reception electric field strength and the adjacent interference wave level for the reception station, and as a result, unnecessary reception switching is repeated. There was a problem that there was.

  Furthermore, in the conventional receiving apparatus, the received electric field strength and the adjacent interference level are measured, and it is determined whether or not the reception switching is performed according to the result. When the reception state of the internal signal wave deteriorates, there is a problem that the state continues and gives the user discomfort.

  The present invention has been made to solve the above-described problems, and selectively desires one of a plurality of signal waves transmitted from a plurality of transmitting stations that transmit signal waves having the same contents with different frequencies. An object of the present invention is to obtain a receiving device that can select a desired wave and perform a good receiving operation with a simple configuration when receiving and outputting as a wave.

  The receiving apparatus according to the present invention selectively receives and outputs one of the signal waves transmitted from a plurality of transmitting stations that transmit signal waves having the same contents with different frequencies as a desired wave. Then, the receiving device is currently receiving when the reception quality determining means for determining the reception quality of the currently received signal wave and the reception quality determining means determine that the reception quality has deteriorated below a predetermined threshold level. Adjacent interference determining means for determining whether or not the signal wave is receiving adjacent interference waves, and when the adjacent interference determining means determines that the adjacent interference waves are being received, signal waves other than the currently received signal wave And a channel selection control means for selecting a transmitting station that transmits the signal wave when it does not receive the adjacent interference wave.

  According to the present invention, when one of signal waves transmitted from a plurality of transmitting stations is selectively received and output as a desired wave, the reception quality of the currently received signal wave is determined, and the reception quality is determined. Is determined to have deteriorated below a predetermined threshold level, it is determined whether or not the currently received signal wave has received an adjacent interference wave, and then it is determined to have received an adjacent interference wave. Since it is configured to select a transmitting station that transmits a signal wave other than the currently received signal wave, and to select the transmitting station when the transmitting station does not receive an adjacent interfering wave, a simple configuration is desired. There is an effect that a good reception state can always be maintained by selecting a wave.

Embodiment 1 FIG.
Here, a radio receiving apparatus used in RDS (transmission system) will be described as an example of the receiving apparatus. Referring to FIG. 1, in RDS, multiplexing is performed by superimposing traffic information and a list of broadcast stations (AF list) that broadcast the same broadcast program as RDS data on FM broadcast signals from a plurality of broadcast stations (transmitting stations). Broadcast signals are being transmitted.

  For example, the radio receiver 10 is mounted on a vehicle, selects one of a plurality of broadcasting stations as a receiving station, receives a multiplexed signal from the receiving station, demodulates an FM broadcast signal, and performs sound processing. While outputting as a signal, as a vehicle moves, a broadcast station that broadcasts the same broadcast program is followed as a receiving station based on RDS data as described later. Note that the multiplexed signals (signal waves) transmitted from each broadcasting station have different frequencies.

  The radio receiver 10 includes a receiver 11 and a microcomputer 12. The receiver 11 includes a high-frequency unit (front end) 21, a detection / intermediate frequency amplifier (IFDET) 22, a stereo demodulation circuit (MPX) 23, and an audio. The circuit 24, the PLL circuit 25, the electric field strength detection circuit 26, the RDS data demodulation circuit 27, and the noise detection circuit 28 are provided. The front end 21 is connected to the antenna 31, and the audio circuit 24 is connected to the speaker 32. Yes. The microcomputer 12 is connected with a PLL circuit 25, an electric field strength detection circuit 26, an RDS data demodulation circuit 27, and a noise detection circuit 28.

  The receiver 11 receives one of the plurality of broadcast stations as a receiving station, and receives a multiplexed signal from the receiving station via the antenna by the front end 21. That is, the front end 21 tunes to a multiplexed signal having a frequency corresponding to the voltage control signal supplied from the PLL circuit 25, receives the multiplexed signal transmitted from the receiving station, and receives an intermediate frequency signal (IF signal). Is output.

  The IFDET 22 amplifies the IF signal and provides it to the MPX 23. The MPX 23 demodulates the FM broadcast signal in the IF signal and provides it to the audio circuit 24 as a demodulated signal. The audio circuit 24 generates an acoustic signal (stereo signal) according to the demodulated signal, and the acoustic signal is output from the speaker 32 as sound.

  On the other hand, an IF signal is applied from the IFDET 22 to the electric field strength detection circuit 26, the RDS data demodulation circuit 27, and the noise detection circuit 28. Then, the RDS data demodulating circuit 27 extracts and demodulates the RDS data in the IF signal and gives it to the microcomputer 12. As shown in FIG. 2, in the microcomputer 12, RDS data is captured by the data capturing unit 12a and is provided as digital data to the data decoding unit 12b. The data decoding unit 12b decodes the digital data and stores it as a decoding information table 12c.

  In the illustrated example, the decryption information table 12c includes an identification code, the number of traffic information stations, a broadcast station name, the number of broadcast stations (hereinafter referred to as AF stations) that transmit the same broadcast program (number of AF stations), The frequency of the AF station is included, and here, the number of AF stations and the frequency of each AF station are the AF list.

  Although not shown, the microcomputer 12 is provided with a channel selection signal for the user to select a broadcast station that broadcasts a desired broadcast program from the channel selection switch, and the microcomputer 12 is tuned according to the channel selection signal. A control signal is given to the PLL circuit 25. The PLL circuit 25 generates a voltage control signal based on the tuning control signal, whereby the front end 21 receives a multiplexed signal having a frequency corresponding to the voltage control signal.

  In addition, the electric field strength detection circuit 26 detects the received electric field strength based on the IF signal and provides it to the microcomputer 12 as a received quality signal indicating the received electric field level. Further, the noise detection circuit 28 detects the multipath interference level and the adjacent interference level for the receiving station currently receiving in accordance with the IF signal, and gives the interference level signal to the microcomputer 12.

  As shown in FIG. 3, the microcomputer 12 includes analog / digital conversion circuits (A / D) 12d and 12e, and the reception quality signal and the interference level signal are A / D converted by the A / D 12d and 12e, respectively. Then, the level is determined by the level determination units 12f and 12h according to the voltage value. In the illustrated example, the received electric field level is divided into 16 stages. For example, when the voltage value of the received electric field level is 0V, level 0, 0.3V, level 1, and 5V, F. Similarly, when the voltage value of the noise level indicated by the interference level signal is 0V, level 0, 0.3V is level 1, and 5V is level F.

  As shown in FIG. 3, a reception quality determination table 12g is set in advance in the microcomputer 12. In the illustrated example, the horizontal axis represents the noise level and the vertical axis represents the received electric field level. Are assigned to the intersections of the received electric field level and the noise level.

  Then, the total level is read from the reception quality determination table 12g according to the electric field determination level and the noise determination level output from the level determination units 12f and 12h, and reception is performed as described later according to the total level. Station switching control is performed.

  Since the radio receiver 10 is mounted on a vehicle, the reception state of a multiplexed signal from a receiving station that is currently receiving deteriorates as the vehicle moves. Therefore, the microcomputer 12 searches the AF list for an AF broadcast station that transmits the same broadcast program as the broadcast station indicated by the channel selection signal, and performs reception station switching control (that is, automatic tracking control is performed). . At the time of automatic tracking control, in order to confirm the reception state from the AF station, it is once detuned from the currently receiving reception station and tuned to the AF station to confirm the reception state. Since abnormal noise may occur, the microcomputer 12 performs audio mute control. Note that this automatic tracking control is performed in an extremely short time, and therefore does not give the user a sense of sound interruption.

  In the automatic tracking control described above, the microcomputer 12 determines the reception state of the AF station according to the reception quality signal and the interference level signal, as described later, and performs switching control of the reception station, that is, automatic Follow-up control is performed.

Next, the operation will be described.
Referring to FIGS. 1 and 4, when radio receiving apparatus 10 is turned on and a user gives a channel selection signal from a channel selection switch, a broadcast station corresponding to the channel selection signal is selected as a reception station. The multiplexed signal transmitted from this receiving station is received by the front end 21. Then, as described above, the microcomputer 12 stores the decoding information table 12c and monitors the reception quality (step ST1). When the reception quality monitoring is activated, the microcomputer 12 executes reception quality level determination (step ST2).

  In step ST2, as shown in FIG. 5, assuming that the frequency of the receiving station is 100 MHz, the microcomputer 12 refers to the decoding information table 12c and makes a comprehensive reception determination of the receiving station (function block). 41). In the comprehensive reception determination, the total level is obtained from the reception determination table 12g according to the reception electric field level and the noise level, and this total level is set as the reception quality level.

  Subsequently, the microcomputer 12 determines whether or not the reception quality is good according to the reception quality level (step ST3). For example, the microcomputer 12 determines that the reception quality has deteriorated when the reception quality level is 8 or less (functional block 42 in FIG. 5).

  If it is determined that the reception quality has deteriorated, the microcomputer 12 looks at the noise level and determines whether or not a noise level exceeding the noise threshold is continuously detected (step ST4). When the noise level is continuously detected, an adjacent frequency adjacent to the frequency of the current receiving station is received (step ST5), and it is determined whether or not adjacent interference has been received (step ST6).

  Referring to FIG. 6, if the noise level 9 continues three times (for 3 seconds), for example (function block 43), the microcomputer 12 starts an adjacent interference check (function block 44), and receives the reception station (frequency 100 MHz). ) Is received, a tuning control signal is given to the PLL circuit 25 (function block 45), and sound muting is applied.

  In response to the voltage control signal output from the PLL circuit 25, the front end 21 receives a transmission signal from an adjacent station (function block 46). The microcomputer 12 determines the received electric field level of the adjacent station (functional block 47), and compares the received electric field level of the receiving station with the received electric field level of the adjacent station (functional block 48).

  In the function block 48, if the received electric field level of the adjacent station−the received electric field level of the receiving station ≦ 2, the microcomputer 12 recognizes the adjacent station as an interfering station (functional block 49). On the other hand, if the received electric field level of the adjacent station−the received electric field level of the receiving station> 2, the microcomputer 12 receives the receiving station (frequency 100 MHz), and therefore gives a tuning control signal to the PLL circuit 25 (function block 50). ), Cancel the audio mute. In response to the voltage control signal output from the PLL circuit 25, the front end 21 receives the multiplexed signal from the receiving station (function block 51).

  Subsequently, in order to receive another adjacent station (frequency 99.9 MHz) adjacent to the receiving station (frequency 100 MHz), the microcomputer 12 gives a tuning control signal to the PLL circuit 25 and transmits a transmission signal of another adjacent station. As described above, it is determined whether or not the station is a disturbing station (electric field level comparison: function block 52).

  If it is determined in step ST4 that noise is not continuously detected, the microcomputer 12 performs reception quality level determination of the AF station every first time (for example, 3 seconds) (step ST7). If the microcomputer 12 determines that it has received the adjacent disturbance, the microcomputer 12 determines the reception quality level of the AF station every second time (for example, 0.5 seconds) shorter than the first time (step) ST8). Then, an AF station candidate is determined according to the reception quality level determination result of the AF station (step ST9).

  In step ST8, the microcomputer 12 lowers the reception quality level of the receiving station and considers that the level is 1, for example.

  Referring again to FIG. 5, in step ST3 of FIG. 4, if the reception quality level of the receiving station is equal to or lower than level 8 in the functional block 42 and noise is not continuously detected, step ST7 of FIG. 4 is executed. Similarly, when the reception quality level of the receiving station is equal to or lower than level 8 in function block 42 and noise is continuously detected and no adjacent interference is received, step ST7 is executed.

  Further, when the reception quality level of the receiving station is equal to or lower than level 8 in the function block 42 and noise is continuously detected and adjacent interference is received, step ST8 is executed.

  In steps ST7 and ST8, the AF station check is permitted (function block 53), and the microcomputer 12 first receives the AF station 1 (frequency 88.1 MHz), so that a tuning control signal is given to the PLL circuit 25 (function). Block 54), audio mute is applied. Then, according to the voltage control signal output from the PLL circuit 25, the front end 21 receives the multiplexed signal from the AF station 1 (function block 55).

  The microcomputer 12 performs overall reception quality determination for the AF station 1 (function block 56), and obtains the reception quality level obtained as a result of the overall reception quality judgment in the function block 56 and the result of the overall reception quality judgment in the function block 41. If the reception quality level of the receiving station is smaller than the reception quality level of the AF station 1, the microcomputer 12 selects the AF station 1 as a candidate for the receiving station and performs audio muting. Release (function block 58).

  On the other hand, if the receiving quality level of the receiving station is equal to or higher than the receiving quality level of the AF station 1, the microcomputer 12 receives the receiving station (frequency 100 MHz), and therefore gives a tuning control signal to the PLL circuit 25 (function block 59). , Cancel audio mute. In response to the voltage control signal output from the PLL circuit 25, the front end 21 receives the multiplexed signal from the current receiving station (function block 60).

  Thereafter, in the same manner, overall reception quality determination is performed for all AF stations existing in the AF list, and the reception quality level of the reception station and the reception quality level of each AF station are compared (function block 61). As described above, in step ST7, for example, the reception quality level of the AF station is determined every 3 seconds, and in step ST8, the reception quality level of the AF station is determined every 0.5 seconds. It will be.

  As described above, when the AF station candidate is determined, the microcomputer 12 determines whether or not the AF station candidate is subjected to adjacent interference (step ST10). Referring to FIG. 7, if an AF station (frequency 88.1 MHz) is determined as an AF station candidate (function block 62), the microcomputer 12 first stores the received electric field level associated with this AF station ( Function block 63).

  Subsequently, in order to receive an adjacent station (frequency 88.2 MHz) adjacent to the AF station (frequency 88.1 MHz), a tuning control signal is given to the PLL circuit 25 (function block 64), and audio mute is applied. In response to the voltage control signal output from the PLL circuit 25, the front end 21 receives the transmission signal from the adjacent station (function block 65). Then, the microcomputer 12 determines the received electric field level of the adjacent station (functional block 66), and compares the received electric field level of the AF station candidate with the received electric field level of the adjacent station (functional block 67).

  In the functional block 67, if the received electric field level of the adjacent station−the received electric field level of the AF station candidate ≦ 2, the microcomputer 12 recognizes the adjacent station as an AF interference station (functional block 68).

  On the other hand, if the reception electric field level of the adjacent station−the reception electric field level of the AF station candidate> 2, the microcomputer 12 receives the AF station candidate (frequency 88.1 MHz), and therefore gives a tuning control signal to the PLL circuit 25. (Function block 69), audio mute is canceled. In response to the voltage control signal output from the PLL circuit 25, the front end 21 receives the multiplexed signal from the AF station candidate (function block 70).

  Subsequently, the microcomputer 12 receives another adjacent station (frequency 88.0 MHz, frequency 88.3 MHz, frequency 87.9 MHz, etc.) adjacent to the AF station candidate (frequency 88.1 MHz). A tuning control signal is provided, and a transmission signal of another adjacent station is received, and it is determined whether or not it is an AF interference station as described above (electric field level comparison: function block 71).

  In step ST10, if the AF station candidate is not subject to adjacent interference, the microcomputer 12 tunes to the AF station candidate and receives a multiplexed signal from this AF station candidate. Then, the microcomputer 12 returns to step ST1. If it is determined in step ST10 that the AF station candidate is subjected to adjacent interference, the microcomputer 12 returns to step ST4 and continues the process.

  As is clear from the above description, the microcomputer 12, the PLL circuit 25, the electric field strength detection circuit 26, the RDS data demodulation circuit 27, and the noise detection circuit 28 are collectively composed of reception quality determination means, adjacent interference determination means, The decoding information table functions as a storage unit.

  As described above, according to the first embodiment, the reception quality of a currently received broadcast wave is determined, and if it is determined that the reception quality has deteriorated below a predetermined threshold level, the currently received broadcast wave is being received. If it is determined whether or not the broadcast wave is receiving an adjacent interference wave, and it is determined that the broadcast wave is receiving an adjacent interference wave, a broadcast station that transmits a broadcast wave other than the currently received broadcast wave is selected and Since the broadcast station is selected when the broadcast wave from the broadcast does not receive the adjacent interference wave, there is an effect that the broadcast wave can always be received satisfactorily with a simple configuration.

  According to the first embodiment, since the reception quality is determined according to the reception electric field level of the broadcast wave currently being received and the noise level of the adjacent interfering wave adjacent to the broadcast wave, the reception quality is accurately determined. There is an effect that the determination can be performed.

  According to the first embodiment, when it is determined that the adjacent interference wave is not received, one of the broadcast stations that transmits a signal wave other than the broadcast wave currently being received at a predetermined first time. If the reception quality of the broadcast wave transmitted from the transmission station is equal to or higher than a predetermined threshold level, the broadcast is determined as a channel selection candidate. There is an effect that it is possible to easily switch the reception when the signal becomes worse.

  According to the first embodiment, when it is determined that the adjacent interfering wave is received, the broadcast station that transmits a broadcast wave other than the currently received broadcast wave every second time shorter than the first time. Since one broadcast station is selected as a channel selection candidate when the reception quality of a broadcast wave transmitted from the broadcast station is equal to or higher than a predetermined threshold level, there is an adjacent interference wave. In this case, there is an effect that the reception switching can be performed in a short time.

It is a block diagram which shows an example of the receiver by Embodiment 1 of this invention as a radio receiver. It is a functional block diagram for demonstrating the operation | movement of AF list storage in the microcomputer shown in FIG. FIG. 2 is a functional block diagram for explaining an operation of determining a reception quality level according to a reception electric field level and a noise level in the microcomputer shown in FIG. 1. 6 is a flowchart for explaining a reception switching operation in the receiving apparatus shown in FIG. It is a functional block diagram for demonstrating the operation | movement for selecting AF station candidate in the microcomputer shown in FIG. It is a functional block diagram for demonstrating the operation | movement for determining presence of the jamming station with respect to a receiving station in the microcomputer shown in FIG. It is a functional block diagram for demonstrating the operation | movement for determining presence of the jamming station with respect to AF station candidate in the microcomputer shown in FIG.

Explanation of symbols

  10 radio receiver, 11 receiver, 12 microcomputer, 12a data capturing unit, 12b data decoding unit, 12c decoding information table, 12d, 12e analog-digital conversion circuit (A / D), 12f, 12h level determination unit, 12g reception Quality judgment table, 21 high frequency section (front end), 22 detection / intermediate frequency amplifier (IFDET), 23 stereo demodulation circuit (MPX), 24 audio circuit, 25 PLL circuit, 26 field strength detection circuit, 27 RDS data demodulation circuit, 28 noise detection circuit, 31 antenna, 32 speaker, 41-71 functional block.

Claims (5)

In a receiving apparatus that selectively receives and outputs one as a desired wave among signal waves transmitted from a plurality of transmitting stations that transmit signal waves of the same content with different frequencies,
Reception quality determination means for determining the reception quality of the signal wave currently being received;
When it is determined by the reception quality determination means that the reception quality has deteriorated below a predetermined threshold level, adjacent interference determination means for determining whether or not the currently received signal wave has received an adjacent interference wave;
When it is determined by the adjacent disturbance determining means that the adjacent interference wave is received, if a signal wave other than the currently received signal wave has not received the adjacent interference wave, a transmitting station that transmits the signal wave is selected. And a channel selection control means.   2. The reception quality determination means according to claim 1, wherein the reception quality determination means determines the reception quality according to a reception electric field level of a signal wave currently being received and a noise level of an adjacent interference wave adjacent to the signal wave. Receiver device. When it is determined by the adjacent disturbance determination means that the channel selection control means has not received the adjacent interference wave, the channel selection control means transmits a signal wave other than the currently received signal wave at a predetermined first time. A first channel selection candidate determining means for selecting one of the transmission stations as a channel selection candidate when the reception quality of a signal wave transmitted from the transmission station is equal to or higher than a predetermined threshold level;
The receiving apparatus according to claim 1, further comprising: a channel selection unit that selects a channel selection candidate when the channel selection candidate does not receive an adjacent interference wave.   When it is determined by the adjacent disturbance determination means that the channel selection control means is receiving the adjacent disturbance wave, the signal other than the signal wave currently being received is received every second time shorter than the first time defined in advance. A second tuning station that selects one of the transmitting stations that transmits the wave and determines the transmitting station as a tuning candidate if the reception quality of the signal wave transmitted from the transmitting station is equal to or higher than a predetermined threshold level. 4. The receiving apparatus according to claim 3, further comprising candidate determination means. The transmission frequency of the transmitting station that transmits the signal wave of the same content is superimposed on each of the signal waves as digital data,
5. The receiving apparatus according to claim 1, further comprising a storage unit that stores the digital data.

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