JP3883280B2 - Multiple broadcast receiver - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention includes two tuners, and the same program broadcast received by one tuner at the other tuner while receiving the multiple broadcast radio wave including the program broadcast and the data multiplexed on the program broadcast. The present invention relates to a multiplex broadcast receiver in which the reception status of the alternative station frequency is checked, and one tuner is made to follow the alternative station frequency with the good reception status.
[0002]
[Prior art]
In multiplex broadcasting, information related to the program broadcast and information such as traffic information are multiplexed on FM radio broadcast airwaves, and the receiving side receives the multiplexed information, so that the listener of the radio broadcast can receive it. There are RDS (Radio Data System) systems that can provide various services.
[0003]
Conventionally, as a radio receiver for receiving such multiplex broadcast radio waves, a single tuner is used and the tuner receives a multiplex broadcast radio wave including a program broadcast and data multiplexed in the program broadcast. Based on the alternative frequency list of the same program broadcast obtained from the multiplex broadcast radio wave, by sequentially switching the reception frequency of the tuner every predetermined time, the alternative frequency for broadcasting the same program is sequentially received, and its reception level And the tuner is made to follow the alternative station frequency of the same program having a good reception level.
[0004]
However, according to the radio receiver using such a tuner, when the follow-up operation is performed on the alternative station frequency of the same program based on the alternative frequency list, the reception frequency is switched instantaneously every predetermined time. Since the audio mute is applied at each switching, there is a situation in which the user is uncomfortable with the sound interruption caused by the mute accompanying the following operation.
[0005]
Therefore, in order to cope with such a situation, a radio receiver having two tuner functions is being proposed.
[0006]
Conventionally, a radio receiver that receives such a multiplex broadcast radio wave has two tuners, and one tuner is receiving a multiplex broadcast radio wave including a program broadcast and data multiplexed in the program broadcast. Based on the alternative frequency list of the same program broadcast obtained from the multiplex broadcast radio wave, the other tuner sequentially receives the alternative frequencies for broadcasting the same program, checks the reception level, and has the same reception level. One tuner is made to follow the alternative station frequency of the program.
[0007]
According to the radio receiver having such a two-tuner function, sound interruption due to mute accompanying the follow-up operation unlike the one-tuner-type radio receiver as described above does not occur, so that the user feels uncomfortable. There is no such thing.
[0008]
[Problems to be solved by the invention]
By the way, in such a multi-broadcasting radio receiver having two tuners in the same casing, each tuner performs a receiving operation in a relationship of local oscillation frequency = reception frequency + intermediate frequency (10.7 MHz) by a PLL circuit. By the damping voltage (reception level) generated when the other tuner performing the AF search checks the reception status of the alternative frequency, the relationship of the reception frequency of one tuner = the reception frequency of the other tuner + the intermediate frequency is There is a problem in that beat noise is generated in the audio output of one tuner at a frequency that holds and a frequency of ± 200 KHz before and after that frequency.
[0009]
That is, in the conventional two-tuner type RDS receiver, when the reception status of the alternative frequency is confirmed by the other tuner that performs the AF search, the next alternative frequency is directly received. As shown in FIG. 5, when the PLL circuit changes the alternative frequency AF1 to the next alternative frequency AF2 (AF1 <AF2) and locks to the alternative frequency AF2, a damping 51 is generated in the tuning voltage (VT) at the initial transition of the frequency. However, the frequency range 52 of the other tuner in which noise is generated is applied to the sound output of the broadcast station received by the one tuner that receives the program broadcast by the damping 51. As a result, the sound output of one tuner is output. The noise is harsh due to damping.
[0010]
FIG. 6 is a diagram showing the relationship between the tuning voltage (VT) and the lock time when the PLL circuit changes the alternative frequency AF1 to the next alternative frequency AF2 (AF1> AF2) and locks to the alternative frequency AF2. As is apparent from FIG. 6, a damping 61 is generated in the tuning voltage (VT) at the initial transition from the alternative frequency AF1 to the alternative frequency AF2, and this damping 61 is received by one tuner receiving a program broadcast. The frequency range 62 of the other tuner in which noise is generated is applied to the sound output of the station, and as a result, unpleasant noise due to damping is generated in the sound output of one tuner.
[0011]
The present invention solves the above-described problems. When a program broadcast is received by one tuner, the other tuner does not generate an audible noise in the audio output of the broadcast station, and the alternative frequency is replaced by the other tuner. It is an object of the present invention to provide a multiplex broadcasting receiver capable of checking the reception state of the receiver.
[0012]
[Means for Solving the Problems]
In order to achieve the above object, the invention described in claim 1 includes first and second tuners, and the first tuner receives a multiplex broadcast radio wave including a program broadcast and data multiplexed in the program broadcast. However, the reception status of the alternative station frequency of the same program broadcast received by the first tuner is checked by the second tuner based on the alternative frequency list obtained from the multiplex broadcast, and the first tuner A receiver for multiplex broadcasting having a control means for following the substitute station frequency in a good reception state, wherein the control means is configured so that the second tuner has a current substitute frequency Fn based on the substitute frequency list. When the next alternative frequency Fn + 1 is received from (1), the frequency of (alternative frequency Fn + 1) + intermediate frequency is the sound of the first tuner with respect to the reception frequency of the first tuner. When it is determined that the first determination unit determines whether or not the output is within a predetermined frequency range where noise is generated, and the first determination unit is within the predetermined frequency range, the second determination unit While changing the alternative frequency of the tuner from the alternative frequency Fn to the next alternative frequency Fn + 1, the tuning voltage applied to change the frequency is supplied to the second tuner in a plurality of stages, so that the next frequency is changed from the alternative frequency Fn. Frequency changing means for changing the frequency of the alternative frequency Fn + 1 in a stepwise manner.
[0013]
According to the first aspect of the present invention, in the first determination unit, the frequency of (alternative frequency Fn + 1) + intermediate frequency is the audio output of the first tuner with respect to the reception frequency of the first tuner. If it is determined that the frequency is within a predetermined frequency range in which noise is generated, the frequency changing means changes the frequency of the second tuner to the second tuner while changing the alternative frequency of the second tuner from the alternative frequency Fn to the next alternative frequency Fn + 1. The second tuner frequency is changed from the alternative frequency Fn to the next alternative frequency while changing the frequency of the next alternative frequency Fn + 1 from the alternative frequency Fn stepwise by supplying the tuning voltage applied for the first and second steps. Since it is changed to Fn + 1, when a program broadcast is received by the first tuner, a frequency range in which noise is generated in the audio output of the broadcast station. So as not to apply to it is possible to eliminate the generation of harsh noise, it is possible to check the reception state of the alternative frequency by the second tuner.
[0014]
According to a second aspect of the present invention, in addition to the configuration of the first aspect of the present invention, after the control means determines that the first determination means is within a predetermined frequency range, the control means It further comprises a second determination means for determining the magnitude relationship between the current alternative frequency Fn and the next alternative frequency Fn + 1.
[0015]
According to the invention described in claim 2 of the present invention, in addition to the effect of the invention described in claim 1, the alternative frequency Fn is determined by determining the magnitude relationship between the alternative frequency Fn and the next alternative frequency Fn + 1. When changing from the alternative frequency Fn to the next alternative frequency Fn + 1 when the frequency is lower than the alternative frequency Fn + 1, the tuning voltage damping does not fall within the frequency range in which noise is generated in the audio output of the broadcast station received by the first tuner. In this way, generation of unpleasant noise can be eliminated.
[0016]
According to a third aspect of the present invention, in addition to the configuration of the first or second aspect of the present invention, the control means is configured such that the first tuner receives the multiplex broadcast while the first tuner is receiving the multiplex broadcast. Based on the alternative station frequency list of the same program broadcast obtained from radio waves, the second tuner sequentially receives frequencies broadcasting the same program, and the electric field strength of the alternative reception frequency is received by the first tuner. It is further characterized by further comprising the same program search means for causing the first tuner to follow the alternative frequency when the received electric field strength of a certain frequency is larger.
[0017]
According to the third aspect of the present invention, the frequency at which the same program is broadcast to the second tuner is sequentially received based on the alternative station frequency list, and the electric field strength of the alternative reception frequency is the first tuner. When the received electric field strength of the frequency being received is larger than the received electric field strength, the follow-up operation can be performed so that the first tuner tunes to the alternative frequency.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
The multiplex broadcast receiver of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a schematic configuration of an RDS receiver to which a multiplex broadcast receiver of the present invention is applied.
[0019]
In FIG. 1, an RDS receiver receives a first broadcast which is received from an antenna 11 and an antenna distributor 12 which receive FM multiplex broadcast radio waves including a program broadcast and RDS data multiplexed in the program broadcast, which are broadcast from a plurality of broadcast stations. The tuner 13 and the second tuner 14 are provided.
[0020]
The first tuner 13 selects a desired station from the FM multiplex broadcast received through the antenna 11 and the antenna distributor 12, converts the received frequency of the station to an intermediate frequency, and amplifies the station. A front end 131 that oscillates a local oscillation frequency OSC1 for detecting a desired broadcast radio wave to be received, and a PLL circuit 132 that obtains a local oscillation frequency OSC1 output from the front end 131 and outputs an error signal E01. A low-pass filter (LPF) 133 that extracts only a low-frequency component from the error signal E01 output from the PLL circuit 132 and outputs the tuning voltage VT1 to the front end 131, and an intermediate frequency amplified by the front end 131. The FM detector 134 for FM detection of the signal and the detection output signal of the FM detector 134 are turned on. Demodulated into a digital signal, and in the case of stereo broadcasting, the multiplexer 135 that separates the audio signal of the L (left) and R (right) channels, and the electric field strength of the received signal being received from the detection output signal of the FM detector 135 are detected. And a noise detector 137 for detecting a noise component related to the reception signal currently being received.
[0021]
A speaker 16 is connected to the output terminal of the multiplexer 133 via an audio amplifier 15 incorporating a volume or the like.
[0022]
The second tuner 14 sequentially receives alternative frequencies from the FM multiplex broadcast received through the antenna 11 and the antenna distributor 12 based on the alternative frequency list (AF list), converts the received frequency to an intermediate frequency, and amplifies it. In addition, a front end 141 that oscillates a local oscillation frequency OSC2 for detecting a desired broadcast radio wave to be received by the second tuner 14, a local oscillation frequency OSC2 from the front end 141, and an error signal E02 are obtained. A PLL circuit 142 that outputs, a low-pass filter (LPF) 143 that extracts only a low frequency component from the error signal E02 output from the PLL circuit 142 and outputs a tuning voltage VT2 to the front end 141, and a front end 141. FM detector 144 for FM detection of the amplified intermediate frequency signal, and this FM An S meter (field strength detection circuit) 145 that detects the electric field strength of the received signal being received from the detection output signal of the waver 144 and a noise detector 146 that detects a noise component related to the currently received received signal. .
[0023]
The respective field strength data detected by the S meters (field strength detection circuits) 136 and 145 are sent via the changeover switch 17 to a control device 18 comprising a microcomputer for controlling the entire RDS receiver.
[0024]
The noise data detected by the noise detectors 137 and 146 is sent to the control device 18 via the changeover switch 19. Further, RDS data, which is a radio data signal extracted from the detection output signals of the FM detectors 134 and 144, is sent to the RDS decoder 21 via the changeover switch 20, and the RDS data demodulated by the RDS decoder 21 is transmitted to the control device. 18 is sent out.
[0025]
The changeover switches 17, 19 and 20 are configured to be simultaneously switched to the first tuner 13 side and the second tuner 14 side by a control signal output from the control device 18, respectively.
[0026]
The RDS data includes data such as an alternative station frequency (AF) list indicating the frequencies of broadcast stations that broadcast the same program, a program identification (PI) code, and a program type (PTY) code indicating the contents of the program. The alternative station frequency list, the program identification code, and the like obtained from the RDS data are stored in the memory 22 connected to the control device 18.
[0027]
The control device 18 is based on the AF list of broadcast stations of the same program received by the first tuner 13 and stored in the memory 22 in a state where the first tuner 13 is receiving the multiplex broadcast. Then, the alternative frequency for broadcasting the same program is sequentially received by the second tuner 14 by outputting a selection command from the control device 18 to the PLL circuit 142, and the reception status of the received frequency is determined by the first tuner 13. Whether the reception state of the received frequency is better or not is determined from the electric field strength detected by both S meters 136 and 145, and the PLL circuit 132 is set so that the first tuner 13 is tuned to the alternative frequency determined to be good. The same program search means 181 that performs a follow-up operation according to a selection command from the control device 18 and the second tuner 14 based on the AF list from the current alternative frequency Fn When the alternative frequency Fn + 1 is received, (alternative frequency Fn + 1) + intermediate frequency (10.5 MHz) is a predetermined frequency that causes noise in the audio output of the first tuner 13 with respect to the reception frequency F0 of the first tuner. First determination means 183 for determining whether or not the frequency is within the frequency range (F0 ± 200 KHz), and after determining that the first determination means 183 is within a predetermined frequency range, the current alternative frequency Fn When the second determination unit 184 that determines the magnitude relationship with the next alternative frequency Fn + 1 and the first determination unit 183 are determined to be within the predetermined frequency range, the alternative frequency of the second tuner 14 is replaced. During the change from the frequency Fn to the next alternative frequency Fn + 1, the tuning voltage VT1 applied to the front end 131 from the PLL circuit 132 through the low-pass filter 133 is changed. And a frequency changing means 185 for incrementally changing the next alternative frequency Fn + 1 frequency from the alternative frequency Fn by supplying in several steps.
[0028]
Next, a processing operation for suppressing noise generation performed by the control device 18 will be described with reference to a flowchart shown in FIG. 2 and explanatory diagrams shown in FIGS. 3 and 4.
[0029]
When the processing program shown in FIG. 2 is started, first, it is determined whether or not the first and second tuners 13 and 14 are receiving (step S1). Here, when both tuners 13 and 14 are not receiving, the processing of the control device 18 is ended. When the receiving operation is being performed, the change-over switches 17, 19 and 20 are switched to the first tuner 13 side, respectively. The decoder 21 extracts an AF list that broadcasts the same program as the broadcast station received by the first tuner 13 from the RDS data based on the PI code. By storing in the area, an AF list is created (step S2).
[0030]
Next, in the second tuner 14, the same program search means 181 is operated by outputting a selection command from the control device 18 to the PLL circuit 141, and the next alternative frequency Fn + 1 is obtained from the current alternative frequency Fn from the AF list. Pick up and change to the next alternative frequency Fn + 1 (step S3). When the second tuner 14 receives the next alternative frequency Fn + 1 from the current alternative frequency Fn by the first determination unit 183, (alternative frequency Fn + 1) + intermediate frequency (10.5 MHz) is the first tuner. It is determined whether the received frequency F0 is within a predetermined frequency range (F0 ± 200 KHz) in which noise is generated in the audio output of the first tuner 13 (step S4).
[0031]
If it is determined that the frequency is out of the predetermined frequency range, the first tuner 13 is caused to follow the same program search means 181 so as to receive the alternative frequency Fn + 1 (step S6).
[0032]
If it is determined in step S4 that the frequency is within the predetermined frequency range, the second determination means 184 determines the magnitude relationship between the current alternative frequency Fn and the next alternative frequency Fn + 1 (step S7).
[0033]
If it is determined that Fn> Fn + 1 is not satisfied, 108.0 MHz is received (step S8), and the process proceeds to step S6 to change from the alternative frequency Fn to the next alternative frequency Fn + 1.
[0034]
FIG. 3 is an explanatory diagram showing the relationship between the tuning voltage and the lock time when Fn <Fn + 1, and the sound output of the broadcasting station in which the first tuner 13 receives the damping voltages 31 and 32 of the tuning voltage VT. Therefore, the tuning voltage VT is dumped 31 when the reception frequency of the first tuner 13 is changed from the alternative frequency Fn to the next alternative frequency Fn + 1. , 32 can be eliminated.
[0035]
If the second determination unit 183 determines in step S7 that Fn> Fn + 1, the frequency changing unit 185 changes the alternative frequency of the second tuner 14 from the alternative frequency Fn to the next alternative frequency Fn + 1. During the change, the tuning voltage VT2 applied to the front end 141 from the PLL circuit 142 through the low-pass filter 143 is supplied in a plurality of stages to change the frequency from the alternative frequency Fn to the next alternative frequency Fn + 1 stepwise. To do.
[0036]
That is, when the frequency change means 185 changes the reception frequency of the second tuner 14 from the alternative frequency Fn to the next alternative frequency Fn + 1, as shown in FIG. 4, first, (Fn + 1) + A (3 MHz). Then, the tuning voltage VT2 applied from the PLL circuit 142 to the front end 141 through the low-pass filter 143 is controlled to cause the second tuner 14 to follow the frequency of (Fn + 1) + A (3 MHz) (step S9). Next, the tuning voltage VT2 applied to the front end 141 from the PLL circuit 142 through the low-pass filter 143 is controlled so as to be (Fn + 1) + B (1 MHz) from the state changed to the frequency of (Fn + 1) + A (3 MHz). Then, the second tuner 14 is caused to follow the frequency of (Fn + 1) + B (1 MHz) (step S10), and then the process proceeds to step S6 to change from the alternative frequency Fn to the next alternative frequency Fn + 1.
[0037]
Therefore, as apparent from FIG. 4, the frequency range 44 of the second tuner 14 in which noise is generated in the audio output of the broadcasting station in which the damping voltages 41, 42, and 43 of the tuning voltage VT are received by the first tuner 13. Nevertheless, it is possible to eliminate the generation of noise due to the tuning voltage VT damping 41, 42, 43 when the reception frequency of the first tuner 13 is changed from the alternative frequency Fn to the next alternative frequency Fn + 1.
[0038]
In the above embodiment, the case where the frequency from the alternative frequency Fn to the next alternative frequency Fn + 1 is changed to two stages or three stages has been described. However, the present invention is not limited to this, and the above embodiments and the above are described. It is also possible to divide into
[0039]
【The invention's effect】
As described above, according to the present invention, in the first determination means, the frequency of (alternative frequency Fn + 1) + intermediate frequency is higher than the reception frequency of the first tuner, and noise is generated in the audio output of the first tuner. If it is determined that the frequency is within a predetermined frequency range to be generated, the frequency changing means changes the frequency of the second tuner from the alternative frequency Fn to the next alternative frequency Fn + 1, and the second tuner changes the frequency. The frequency of the second tuner is changed from the alternative frequency Fn to the next alternative frequency Fn + 1 while gradually changing the frequency of the next alternative frequency Fn + 1 from the alternative frequency Fn by supplying the applied tuning voltage in a plurality of stages. As a result, when the program broadcast is received by the first tuner, the frequency range in which noise is generated in the audio output of the broadcast station is not applied. Unishi Te can be eliminated occurrence of harsh noise, it is possible to check the reception state of the alternative frequency by the second tuner.
[0040]
According to the present invention, by determining the magnitude relationship between the alternative frequency Fn and the next alternative frequency Fn + 1, the change from the alternative frequency Fn to the next alternative frequency Fn + 1 when the alternative frequency Fn is smaller than the next alternative frequency Fn + 1. Occasionally noise generation can be eliminated by preventing the tuning voltage dumping from reaching the frequency range where noise is generated in the audio output of the broadcasting station that is received by the first tuner.
[0041]
Further, according to the present invention, the frequency at which the same program is broadcast to the second tuner is sequentially received based on the alternative station frequency list, and the electric field strength of the alternative reception frequency is the frequency received by the first tuner. When the received electric field strength is larger than the received frequency, the follow-up operation can be performed so that the first tuner tunes to the alternative frequency.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a schematic configuration of an RDS receiver to which a multiplex broadcast receiver of the present invention is applied.
FIG. 2 is a flowchart showing an operation procedure of the RDS receiver in the embodiment of the present invention.
FIG. 3 is an operation explanatory diagram for noise suppression by stepwise control of a tuning voltage in the embodiment of the present invention.
FIG. 4 is an operation explanatory diagram for noise suppression by stepwise control of the tuning voltage in the embodiment of the present invention.
FIG. 5 is an operation explanatory diagram for noise suppression by stepwise control of a tuning voltage in the related art.
FIG. 6 is an operation explanatory diagram for noise suppression by stepwise control of a tuning voltage in the related art.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 11 Antenna 12 Antenna distributor 13 1st tuner 14 2nd tuner 18 Control apparatus 181 Same program search means 183 1st determination means 184 2nd determination means 185 Frequency change means

Claims (3)

A first tuner and a second tuner, the first tuner receiving a multiplex broadcast radio wave including a program broadcast and data multiplexed in the program broadcast, based on an alternative frequency list obtained from the multiplex broadcast; Control means for checking the reception status of the alternative station frequency of the same program broadcast received by the first tuner in the second tuner and performing an operation of following the alternative station frequency having the good reception status in the first tuner. A multiplex broadcast receiver comprising:
The control means includes
When the second tuner receives the next alternative frequency Fn + 1 from the current alternative frequency Fn based on the alternative frequency list, the frequency of (alternative frequency Fn + 1) + intermediate frequency becomes the reception frequency of the first tuner. In contrast, first determination means for determining whether or not the sound output of the first tuner is within a predetermined frequency range in which noise is generated;
If it is determined that the first determination means is within a predetermined frequency range, the second tuner is changed to the second alternative frequency Fn + 1 while the alternative frequency of the second tuner is changed from the alternative frequency Fn to the next alternative frequency Fn + 1. And a frequency changing means for changing the frequency of the next alternative frequency Fn + 1 from the alternative frequency Fn in stages by supplying a tuning voltage applied for changing the frequency in a plurality of stages. Receiving machine. The control means includes
After the first determining means is determined to be within a predetermined frequency range, it further comprises second determining means for determining a magnitude relationship between the current alternative frequency Fn and the next alternative frequency Fn + 1. The multiplex broadcast receiver according to claim 1. The control means includes
While the first tuner is receiving multiplex broadcasting, the frequency that is broadcasting the same program to the second tuner is sequentially received based on the alternative station frequency list of the same program broadcasting obtained from the multiplex broadcasting radio wave. And the same program search that causes the first tuner to tune to the alternative frequency when the electric field strength of the alternative reception frequency is higher than the reception electric field strength of the frequency received by the first tuner. The multiplex broadcast receiver according to claim 1, further comprising means.

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