JPH05218935A - Receiver - Google Patents

Abstract

PURPOSE:To prevent occurrence of jump malfunction by checking the identity of the content of a program for a transmission signal being received and a transmission signal received newly prior to the changeover of a reception transmission signal attended with deterioration in quality of the reception signal. CONSTITUTION:A remote/near changeover circuit 2 selects whether a received station is a remote distance station or a near distance station based on a selection signal SC from a controller 12, an FM front end 3 and a phase synchronization circuit 14 are cooperative to receive the transmission signal of a desired carrier frequency. In this case, the desired station is selected by using a channel selection signal FDT fed to the circuit 14 and after an intermediate frequency amplifier and detection circuit 4 amplifies an intermediate frequency signal from the front end 3, the signal is detected and a low frequency signal is generated. Then a multiplexer 5 generates a stereo signal through a prescribed processing and a mute circuit 6 interrupts tentatively the transmission of a stereo signal based on a mute signal MUT from the controller 12. Then the electric field intensity of the transmission signal is measured by utilizing the interrupting time to discriminate the propriety of the signal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention transmits main information and additional information using subcarriers on one carrier and transmits the information of the same program content as a transmission signal of a plurality of carrier frequencies. Used in a transmission system, constantly monitors the quality of a transmission signal being received, and when the quality deteriorates, a transmission signal of a plurality of carrier frequencies having the same program content as the program content of the transmission signal being received. The present invention relates to a receiving device which checks the above item and switches to reception of another transmission signal having better quality than the transmission signal being received.

[0002]

2. Description of the Related Art Main information such as a stereo broadcast signal and additional information such as data using a sub-carrier are transmitted on one carrier, and the information of the same program content is transmitted by a plurality of carrier frequencies. A receiving device used in a transmission system for transmitting as is known as a receiving device such as an RDS (radio data system) which has been put into practical use in Europe, and this receiving device is usually provided in a vehicle. ing.

As described above, since this type of receiving apparatus is usually used for vehicle installation, the quality of the transmission signal being received changes momentarily with the movement of the vehicle, and the transmission signal is changed. When the quality of (1) deteriorates considerably, the reception state becomes poor and it becomes difficult to hear, and in some cases, the reception state becomes impossible.

Therefore, in this type of receiving apparatus,
The control unit constantly monitors the quality of the transmission signal being received, and when the control unit determines that the quality of the transmission signal has fallen below a predetermined level while monitoring the quality of the transmission signal, the same program as the transmission signal is received. Checking transmission signals of other carrier frequencies having contents, so-called AF (alternative fre)
quencies) search, the result of this AF search,
The switching is performed so that the other transmission signal having a better quality than the transmission signal being received is received.

Thus, the above-mentioned receiving device of this type is
When the quality of the transmission signal being received falls below a predetermined level, the transmission signal of the best quality among the transmission signals of a plurality of carrier frequencies having the same program content as the transmission signal being received is received. Therefore, it has an advantage that the quality of the received signal can be maintained within a certain range.

On the other hand, in one broadcast network area in which a plurality of broadcast stations are used as a unit, in a single broadcast network area, as described above, the plurality of broadcast stations each transmit a plurality of carrier frequencies having the same program content. Even if it is configured to transmit a signal, in another broadcast network area adjacent to the broadcast network area, transmit a transmission signal having the same carrier frequency as any one of the plurality of carrier frequencies. Even in the case of a broadcasting station, the program content of the transmission signal is often different from the same program content.

[0007]

By the way, a vehicle equipped with the above-mentioned receiving device of this type is in a single broadcasting station network area and is transmitted from another broadcasting station network area adjacent to it. In the case where the vehicle moves from within the single broadcasting station network area to within another broadcasting station network area, although the above-described advantages can be enjoyed if the influence of the transmission signal is not great. Or, when moving in the boundary area of the single broadcasting station network area, etc., other quality having better quality than the transmission signal being received which is transmitted in the single broadcasting station network area. The transmission signal transmitted in the broadcasting station network area is received.

In the case where the above-mentioned receiving device mounted on a vehicle is a receiving device having one front end (usually, most receiving devices of this type are of this type), When the vehicle moves as described above, if the quality of the transmission signal being received falls below a predetermined level, the reception signal is being received in another broadcasting station network area having better quality than the transmission signal being received. The transmission signal is switched to a new transmission signal having the same carrier frequency, but since the program content of the new transmission signal is different from the program content of the reception signal being received, the transmission signal being received is again changed. There is a problem that a phenomenon of being switched (here, the phenomenon is referred to as a jump malfunction) occurs, and a listener of the receiving device has to hear an unpleasant sound during the jump malfunction. That.

Further, the jump malfunction is the same program content as the program content of the transmission signal being received in the single broadcasting station network area, which has a better quality than the transmission signal being received. It is also caused by switching to a transmission signal in another broadcasting station network area having the same carrier frequency as the other carrier frequency.

The present invention eliminates the above-mentioned problems, and a first object of the present invention is to provide a transmission signal which is being received prior to switching of the reception transmission signal due to deterioration of the quality of the reception signal. It is an object of the present invention to provide a receiving device which checks the identity of program contents with a newly received transmission signal and prevents jump malfunction.

A second object is to switch the received transmission signal due to the deterioration of the quality of the received signal before the transmission signal being received and the transmission signal newly received when the transmission signal being received is silent. The purpose of the present invention is to provide a receiving device that checks the identity of the program contents with and prevents occurrence of jump malfunction.

[0012]

In order to achieve the first object, according to the present invention, the main information and the additional information using the sub-carrier are transmitted on one carrier and the same program content is transmitted. Used in a transmission system for transmitting the information as a transmission signal having a plurality of carrier frequencies, constantly monitoring the quality of the transmission signal being received, and when the quality is deteriorated, it is the same as the program content of the transmission signal being received. In the receiving device for checking the transmission signals of the other plural carrier frequencies of the program content and switching to the reception of another transmission signal having a better quality than the transmission signal being received, the reception signal and the other And the transmission information of the program are alternately sampled, and these sampling informations are digitally compared to check the identity of the program content between the transmission signal being received and the other transmission signal. Comprising one of the means.

Further, in order to achieve the second object, according to the present invention, main information and additional information using a sub-carrier are transmitted on one carrier and are transmitted, and a plurality of the information having the same program content is transmitted. It is used in a transmission system for transmitting as a transmission signal of the carrier frequency of, and constantly monitors the quality of the transmission signal being received, and when the quality deteriorates, the same program content as the program content of the transmission signal being received is received. In a receiving device that performs a check of a plurality of other carrier frequencies and switches to reception of another transmission signal having better quality than the transmission signal being received, when the transmission signal being received is in a silent state, Other transmission signals are sampled, it is judged whether or not the sampling information is digitally silent, and it is checked whether the transmission contents being received and the other transmission signals have the same program content. Comprising a second means for click.

[0014]

According to the first means, while the quality of the transmission signal being received is being monitored, the quality of the transmission signal being received is deteriorated and another transmission signal having a better quality is generated. In this case, the transmission signal being received and the other transmission signal are alternately sampled, these sampling outputs are converted into digital signals, and then the two digital signals are based on the signal envelopes indicated by the digital signals. Of the program contents of the transmission signal being received and the program contents of the other transmission signal are judged from the comparison result, and the sameness of the program contents can be confirmed by the judgment. In this case, the reception is switched from the transmission signal being received to the other transmission signal. On the other hand, when it is not possible to confirm the identity of the program content by the judgment, it is possible to determine the second best quality. To compare the sampling and digital signal as described above with respect to the transmission signal.

According to the second means, when the silenced state of the receiving transmission signal is detected while monitoring the quality of the receiving transmission signal, the best quality at that time is detected. After sampling the other transmission signal and converting the sampling output into a digital signal, the other transmission signal is silenced in the same manner as the transmission signal being received based on the signal envelope indicated by the digital signal. It is determined whether or not there is, and from the detection result, the program content of the transmission signal being received is judged to be the same as the program content of the other transmission signal. Is confirmed, the transmission signal being received is changed from the transmission signal being received to the other transmission signal at the time when the quality of the transmission signal being received is deteriorated and the quality of the other transmission signal is improved. Performs switching of reception, whereas, wherein when the identity of the program content can not be confirmed by determining, with respect to sub-optimal good other transmission signal quality to detect the sampling and digital signal as described above.

As described above, according to the present invention, prior to the switching of reception from the transmission signal being received to another transmission signal,
Since the identity of the program contents of the transmission signal being received and another transmission signal is checked, a jump malfunction does not occur at the time of switching the reception, and the listener must hear an unpleasant sound at the time of this switching. The harmful effect of not becoming can be eliminated. Further, even if the above-mentioned check is performed, the time required for the check is instantaneous, so that there is no interruption of the recognizable voice.

[0017]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of the first embodiment of the receiving apparatus according to the present invention.

In FIG. 1, 1 is a receiving antenna, 2 is a perspective switching circuit, 3 is an FM front end, 4 is an intermediate frequency amplification / detection circuit, 5 is a multiplexer (MPX), 6 is a mute circuit, and 7 is output amplification. Circuit, 8 is a speaker, 9
Is an RDS decoder, 10 is a signal meter (S meter), 11 is a station detection circuit, 12 is a controller (control section), 13 is an operation section, and 14 is a phase synchronization circuit (P).
LL) and 15 are analog-digital circuits.

The near / far switching circuit 2 switches the station to be received by the selection signal SC from the controller 12 between the far station and the near station. The FM front end 3 cooperates with the phase synchronization circuit 14 to receive a transmission signal of a desired carrier frequency, and the selection of the desired station is performed by the controller 12 which supplies the channel selection signal FDT to the phase synchronization circuit 14. Done by. The intermediate frequency amplification / detection circuit 4 amplifies the intermediate frequency signal from the FM front end 3 and then detects the signal to generate a low frequency signal. The multiplexer 5 performs a predetermined process on the low frequency signal to generate a stereo signal. The mute circuit 6 receives the silence signal MU from the controller 12.
T temporarily interrupts the transmission of the stereo signal. The output amplifier circuit 7 amplifies the stereo signal and causes the speaker 8 to emit the sound. The RDS decoder 9 extracts the RSD data contained in the low frequency signal and supplies it to the controller 12. Signal meter 1
0 measures the electric field strength of the transmission signal being received by measuring the strength of the intermediate frequency signal, and the measurement result S
M is supplied to the controller 12 to determine the quality of the transmission signal or the like being received. Station detection circuit 11
Is within the frequency deviation of the transmission signal being received and supplies the detection signal SD to the controller 12 when the signal strength is equal to or higher than the set level, and another transmission signal (another receiving station) exists. Make a decision. The operation unit 13 has a plurality of operation keys, and gives a command to be controlled to the controller 12 by operating the operation keys. The analog-digital circuit 15 alternately samples the stereo signal being received and another stereo signal in accordance with a command from the controller 12, converts the sampling signal into a digital signal, and supplies the digital signal to the controller 12.

Since all the constituent elements other than the analog-digital circuit 15 are constituent elements included in the conventional receiving apparatus of this type, further detailed description of these constituent elements will be omitted.

FIG. 2 is a waveform diagram for explaining the operation of the receiving apparatus according to the above configuration.

In FIG. 2, (a) is a signal waveform of a stereo signal (hereinafter referred to as a received signal) obtained from a transmission signal being received, and (b) is obtained from another transmission signal of the highest quality. Signal waveform of the obtained stereo signal (hereinafter referred to as a new reception signal), (c) extracts the positive and negative components of the reception signal and the new reception signal, and (d) extracts the positive and negative components of the reception signal and the new reception signal. Half-wave switch signal waveform, (e) a sampling signal waveform for sampling the received signal and a new received signal, (f) a sampling waveform of the received signal,
(G) is a sampling waveform of a new received signal.

The operation of the first embodiment of the receiving apparatus according to the present invention will be described below with reference to the waveform diagrams. In this operation, the description of the same operation as that of the conventional receiving apparatus of this type will be omitted.

First, when the controller 12 monitors the electric field strength of the received signal by looking at the output of the signal meter 10, the electric field strength of the received signal is lower than a predetermined level (the quality of the received signal is within a predetermined range). Drop,
If a new received signal having the same frequency as the received signal and a larger electric field strength than the received signal (better than the quality of the received signal) can be confirmed, the controller 12
During the period from the time t ₀ to the time t ₈ shown in FIG. 2, the muting signal MUT is supplied to the mute circuit 6 to temporarily suspend the output of the reception signal (a) from the speaker 8. At the same time, the controller 12 starts from time t ₀ to time Δt.
A sampling signal (e) whose polarity is inverted every time and a switch signal (d) whose polarity is inverted every time 2Δt from the time t ₀ are supplied to the analog-digital circuit 15.

Subsequently, the analog-digital circuit 15 is
The received signal (a) is sampled during the positive polarity period of the sampling signal (e), and the new received signal (b) is sampled during the negative polarity period of the sampling signal (e). A sampling waveform (f) of the received signal and a new sampling waveform (g) of the received signal are generated.

That is, from time t ₀ to time t shown in FIG.
_{Since 1} , from time t ₂ to time t ₃ , from time t ₄ to time t ₅ , and from time t ₆ to time t ₇ are positive polarity periods of the sampling signal (e), respectively,
Sampling of the received signal (a) is performed in each of the above periods, and a sampling waveform (f) of the received signal as shown in FIG. 2 is obtained. On the other hand, from time t ₁ to time t ₂ ,
Since the time t ₃ to the time t ₄ , the time t ₅ to the time t ₆ , and the time t ₇ to the time t ₈ are the negative polarity periods of the sampling signal (e), respectively. Sampling is performed on the new received signal (b), and the sampling waveform (g) of the new received signal as shown in FIG. 2 is obtained.

Further, the analog-digital circuit 15 is
The sampling waveform (f) of the received signal and the sampling waveform (g) of the new received signal are each converted into a digital signal, and the converted digital signal is supplied to the controller 12.

At this time, the controller 12 compares the envelopes of the received signal and the new received signal from the two digital signals by the N-point approximation method of comparing a plurality of corresponding points, and It is determined whether or not the two digital signals are the same, that is, whether or not the content of the program of the received signal and the content of the program of the new received signal match.

When the controller 12 determines that the content of the program of the received signal and the content of the program of the new received signal match as a result of the determination, the controller 12 extracts the received signal from the received signal. Switching of the received transmission signal to the new received signal of higher quality is performed according to a normal mode, while the content of the program of the received signal does not match the content of the program of the new received signal. If it is determined that there is, the comparison and determination are sequentially performed for the new received signal that is suboptimal and the suboptimal in terms of the magnitude of the electric field strength. When a new reception signal having contents is not found, the switching operation of the reception transmission signal is held so that the reception of the reception signal is continued. .

In this case, regarding the sampling, the received signal and the new received signal are sampled for two sampling periods,
That is, since the switching is performed at intervals of 2Δt, the sampling accuracy can be improved.

As described above, in the present embodiment, the identity of the program content between the received signal and the new received signal is checked before switching the reception from the received signal to the new received signal. In addition, since the time required for the check is instant, the jump malfunction does not occur at the time of switching the reception, and the listener does not hear an uncomfortable sound generated at the time of the switching.

Next, FIG. 3 is a block diagram showing the configuration of the second embodiment of the receiving apparatus according to the present invention.

In FIG. 3, the same components as those shown in FIG. 1 are designated by the same reference numerals.

The configuration of FIG. 3 is different from the configuration of FIG. 1 only in that the controller 12 monitors the silence of the output stereo signal of the mute circuit 6, and the other points are the configurations of both. Are apparently the same.

Next, FIG. 4 is a waveform diagram for explaining the operation of the second embodiment of the receiving apparatus according to the present invention.

In FIG. 4, (a) is a signal waveform of a stereo signal obtained from a transmission signal being received (hereinafter, this is also referred to as a reception signal), and (b) is another transmission signal of the highest quality. A signal waveform of a stereo signal (hereinafter also referred to as a new reception signal) obtained from the above, (c) is a silence period of the reception signal, (d) is a sampling signal waveform for sampling the new reception signal, ( e) is a sampling waveform of a new received signal.

The operation of the second embodiment of the receiving apparatus according to the present invention will be described below with reference to the waveform chart of FIG. In this operation, the description of the same operation as that of the conventional receiving apparatus of this type will be omitted.

The controller 12 monitors the silent state of the received signal (the output stereo signal of the mute circuit 6) (a),
When the received signal becomes silent immediately before the time t ₀ shown in FIG. 4, the mute circuit MUT is supplied to the mute circuit 6 during the period from the time t ₀ to the time t _4, and the speaker 8 of the received signal (a) 8 is supplied. Temporarily interrupts the vocalization from. At the same time, the controller 12 supplies the analog-digital circuit 15 with the sampling signal (c) in which the non-sampling period and the sampling period are repeated every time Δt from the time t _0.
Supply to.

At this time, the analog-digital circuit 15
Performs sampling on the new received signal (b) during the sampling period of the sampling signal (c),
A sampling waveform (e) of a new received signal is generated.

That is, from time t ₀ to time t shown in FIG.
_{From 1} to time t ₂ to time t ₃ are non-sampling periods of the sampling signal (c), so that the new received signal (b) is not sampled during these periods. From t ₁ to time t ₂ , and from time t ₃ to time t ₄ are the sampling period of the sampling signal (c), the new reception signal (b) is sampled during each period, and A new received signal sampling waveform (e) as shown in FIG. 4 is obtained.

Further, the analog-digital circuit 15 is
The new sampling waveform (e) is converted into a digital signal, and the converted digital signal is transferred to the controller 12
Supply to.

At the time of supplying the digital signal, the controller 12 detects the envelope of the new received signal from the digital signal, and the envelope corresponds to the envelope when there is almost no sound like the received signal. It is determined whether or not the content of the program of the received signal and the content of the program of the new received signal match.

When the controller 12 determines that the content of the program of the received signal and the content of the program of the new received signal match as a result of the determination, the controller 12 compares the received signal with the received signal. Then, when the quality of the new received signal becomes better, switching of the received transmission signal from the received signal to the new received signal is performed according to a normal mode, while the program of the received signal is changed. If it is determined that the contents of the above-mentioned and the contents of the program of the new received signal do not match, then the next-highest degree of the electric field strength and the next-highest-order new received signal are sequentially described above. If no new received signal having the same program content as that of the received signal is found by this comparison and determination, the received signal is received. And it is to be held the switching operation of the receiving transmission signals to continue.

As described above, also in the second embodiment, the identity of the program contents of the received signal and the new received signal is checked before switching the reception from the received signal to the new received signal. Moreover, since the time required for the check is instantaneous, the jump malfunction does not occur at the time of switching the reception, and the listener does not hear an unpleasant sound generated at the time of the switching.

In the above description, it is explained that the operation of the first embodiment and the operation of the second embodiment are carried out separately, and in the present invention, the first operation is carried out. Needless to say, the operation of the embodiment and the operation of the second embodiment are separately performed so that the operation of the second embodiment and the operation of the second embodiment are separately performed, but in addition, the two operations are simultaneously performed. Naturally, such a configuration is also included. Then, in a configuration in which the above two operations are simultaneously performed,
The operation of the second embodiment, which is executed when the received signal is muted, is preferentially performed.

Further, the period required for checking the identity of the program content between the received signal and the new received signal, that is, the silence period of the received signal, shown in each of the above-mentioned embodiments, is simply For example, the period is preferably as short as possible within the range where the check can be performed, and the time Δt is also preferably a short time of about microsecond (μs).

[0048]

As described above, according to the present invention, the new received signal having a quality better than that of the received signal is confirmed prior to the switching of the reception from the received signal to the new received signal. If it is possible and / or if it can be confirmed that the received signal is in the silent state, the program content of the received signal and the new received signal are checked for the sameness. There is an effect that a jump malfunction does not occur at the time of switching and the listener does not hear an unpleasant sound generated at the time of switching.

Further, even when the above-mentioned check is performed, the time required for the check is instantaneous, and there is an effect that the voice is not interrupted enough for the listener to recognize.

[Brief description of drawings]

FIG. 1 is a block configuration diagram showing a configuration of a first embodiment of a receiving apparatus according to the present invention.

FIG. 2 is a waveform diagram for explaining the operation of the first embodiment.

FIG. 3 is a block configuration diagram showing a configuration of a second embodiment of a receiving apparatus according to the present invention.

FIG. 4 is a waveform diagram for explaining the operation of the second embodiment.

[Explanation of symbols]

 1 reception antenna 2 perspective switching circuit 3 FM front end 4 intermediate frequency amplification / detection circuit 5 multiplexer (MPX) 6 mute circuit 7 output amplification circuit 8 speaker 9 RDS decoder 10 signal meter 11 station detection circuit 12 controller (control section) 13 Operation unit 14 Phase synchronization circuit (PLL) 15 Analog-digital circuit

Claims (2)

[Claims] 1. A transmission system for transmitting main information and additional information using subcarriers on a single carrier and transmitting the information of the same program content as a transmission signal of a plurality of carrier frequencies, The quality of the transmission signal being received is constantly monitored, and when the quality is deteriorated, transmission signals of a plurality of carrier frequencies having the same program content as the program content of the transmission signal being received are checked, In a receiving device that switches to reception of another transmission signal of better quality than the transmission signal being received, the transmission signal being received and the other transmission signal are alternately sampled, and these sampling information are digitally compared. Then, the receiving device is characterized in that the program content of the transmission signal being received and the other transmission signal are checked for identity. 2. A transmission system in which main information and additional information using subcarriers are placed on one carrier and transmitted, and the information having the same program content is transmitted as a transmission signal having a plurality of carrier frequencies. The quality of the transmission signal being received is constantly monitored, and when the quality is deteriorated, a plurality of carrier frequencies of the same program content as the program content of the transmission signal being received are checked, In a receiving device that switches to reception of another transmission signal of better quality than the transmission signal, when the transmission signal being received is in a silent state, sampling of the other transmission signal is performed,
A receiving device, characterized in that the sampling information is digitally judged to be silent, and the program contents of the transmission signal being received and the other transmission signal are checked for identity.