JPH0612864B2 - Network receiver - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a network receiving device, and particularly to a network receiving device which is installed in an automobile or the like and which broadcasts the same program, and can always maintain a good receiving state. And a receiving device.

[Prior art]

For example, in Japan and European countries, some radio broadcasting stations are networked and broadcast almost the same program except local programs. Then, when listening to one of these networked broadcasting stations and moving a long distance by, for example, an automobile, the electric field strength becomes small at the end of the service area of the broadcasting station, and the reception quality deteriorates. In such cases,
By searching for a second station that broadcasts the same program, that is, a network station and receiving and listening by the second station, it is possible to continuously listen to the program having the same content in a good reception state.

FIG. 4 shows a conventional receiver used for such a purpose. The device shown in FIG. 1 is composed of an antenna 1, a tuner 2, a power amplifier 3, a speaker 4, a processor 5, a network frequency memory 6 and the like. The network frequency memory 6 is composed of, for example, a read only memory (ROM), and corresponds to each network number or name N ₁ , N ₂ , ..., N _n , and broadcast station frequencies f ₁₁ , f ₁₂ , ..., Of each network. _{f 1K; f 21, f 22} , ...,
_{f 2 l; ...; f n1} , f n2, ..., and stores the f _nm.

In order to continuously listen to the same program in such a conventional receiving apparatus, first, the network frequency memory 6 is searched from the frequency of the broadcasting station currently being listened to, and the network number or name to which the broadcasting station belongs is detected. Remember.
Next, when the electric field strength of the broadcasting station currently being listened to decreases and it is judged that the end of the service area has been reached, the listening is temporarily interrupted, that is, muting is performed, and the broadcasting belonging to the previously stored network number is interrupted. The frequency of the station is read from the network frequency memory 6 and sequentially searched and received. The receiving frequency of the tuner 2 is switched to the newly detected frequency at the time of receiving a broadcast station with an electric field strength of a predetermined level or more, or at the time of detecting the station with the highest electric field strength, and the muting is released to cancel the reception device. Is set to the listening state.

However, in the receiving apparatus as described above, since only the broadcasting station stored in the network frequency memory configured by the read-only memory is searched, it is difficult to cope with the new broadcasting station. It was Furthermore, even stations belonging to the same network number sometimes broadcast different programs such as local programs. In such a case, it is impossible to continuously listen to the same program. there were.

Further, when the audio output signals of the first and second tuner units are compared in level at a plurality of time points and the identity of the broadcasting stations received by the first and second tuner units is judged from the comparison result, It is necessary to set the output levels of the first and second tuner sections to be equal to the reception input of the same broadcast content. However, if the output levels of the first and second tuner units are set to be the same, a difference in received electric field strength due to a distance difference with each broadcasting station, a variation in each tuner unit,
It is almost impossible due to the influence of external factors.

Therefore, it is conceivable that these effects are eliminated by obtaining the level ratios of the audio output signals of the first and second tuner units at a plurality of time points and calculating the relative change ratios thereof. The electric field strength changes at each broadcasting station (reception frequency), and it is difficult to completely remove the effect. Also, since complicated processing is involved in such processing, it is necessary to confirm that the same broadcasting content is used. The time required for detection becomes long, and there arises a problem that the configuration becomes complicated.

[Problems to be solved by the invention]

In view of the above-mentioned problems in the conventional art, the present invention provides a network receiving apparatus, which can reduce the reception quality deterioration due to the reduction of the electric field strength at the service area edge of the broadcasting station being listened The purpose is to automatically switch to a different broadcasting station to enable continuous listening of the same program, to cope with the establishment of a new network broadcasting station, and to eliminate local programs of the network broadcasting station. And

Further, in view of the above conventional problems, the present invention is not affected by a difference in received electric field strength due to a distance difference from each broadcasting station, a variation in the first and second tuner units, an influence of an external factor, and the like. It is possible to reliably detect the identity of broadcast content,
Further, it is possible to provide a network receiving device capable of shortening the time required for detection and simplifying the configuration.
The purpose is to

[Means for solving problems]

According to the present invention, the first tuner unit includes the first tuner unit, the second tuner unit, the comparison unit that compares the received contents of the first tuner unit and the second tuner unit, and the control unit. Is a network receiving device that selects a second broadcast station having the same content as the first broadcast station being received by the second tuner unit by the second tuner unit, wherein the comparison unit is a receiver of the first and second tuner units. A low-pass filter having the same characteristics for removing high frequency components of an audio output signal, a waveform shaping circuit for converting each output of the low-pass filter into a zero crossing wave, and a phase for detecting a phase difference between the outputs of the waveform shaping circuit. It comprises a comparator and a comparator for comparing a signal obtained by smoothing the output of the phase comparator with a reference voltage to derive an identification signal indicating the identity of the broadcast content, and the comparator of the first and second tuner sections. Audio output The second broadcast station is detected by comparing the instantaneous phases of the signals to determine the identity of the broadcast content, and the control unit detects that the second broadcast station is the same as that of the first broadcast station. There is provided a network receiving device characterized in that when the received electric field strength becomes smaller than a predetermined value, the second broadcasting station performs reception instead of the first broadcasting station.

[Work]

According to the above configuration, by using the above-described means, the second station of the same program as the first station currently being received and listened to is detected by determining the identity of the broadcast content, so that the network broadcast station It is possible to accurately continue listening to the same program as excluding local programs and the like. Further, unlike the conventional case, the second station is detected according to the broadcast contents without using the network frequency memory, so that it is possible to cope with the new establishment of the network broadcast station.

Moreover, according to the above configuration, since the instantaneous phases of the audio output signals of the first and second tuner units are compared to determine the identity of the broadcast contents, the audio output signals of the first and second tuner units are determined. Is not affected by the fluctuations in the level of, and therefore is not affected by the difference in the received electric field strength due to the distance difference with each broadcasting station, the variations in the first and second tuner units, and the external factors. It is possible to reliably detect the identity of the broadcast content, and since it does not require a complicated calculation as in the conventional case, the time required for the detection can be shortened and the configuration can be simplified.

〔Example〕

FIG. 1 shows an outline of a network receiving apparatus as an embodiment of the present invention. The device shown in the figure is for identifying the identity of the program content based on the magnitude of the instantaneous phase difference between the audio output signals of the two tuners. The antenna 7, the main tuner 8, the sub tuner 9, the power amplifier 10, the speaker 11, In addition to the processor 16, the tuning operation switch and the display unit 17, a low-pass filter 30 connected to the outputs of the main tuner 8 and the sub tuner 9, respectively.
And the waveform shaping circuit 31, the low-pass filter 32, the waveform shaping circuit 33, and the phase comparison circuit to which the outputs of the waveform shaping circuits 31 and 33 are input, that is, the exclusive OR circuit 3
4, a reduction filter 35, a voltage comparator 36, and the like. The low pass filters 30 and 32 are filters having the same characteristics for removing noise and high frequency components of the audio output signals of the main tuner 8 and the sub tuner 9, respectively. The waveform shaping circuits 31 and 33 convert the outputs of the low pass filters 30 and 32 into zero cross waves. Phase comparison circuit 3
Reference numeral 4 is for detecting the presence or absence of a phase difference by comparing the phases of these zero crossing waves. Low pass filter 35 is to convert the phase comparator output pulse of the phase comparator 34 into a DC voltage, the phase difference is compared with a reference voltage E _t to the DC voltage by the voltage comparator 36 detects whether less than a predetermined value Then, an identification signal is created and applied to the processor 16.

FIGS. 2 (a) and 2 (b) show waveforms at various parts in the apparatus shown in FIG. Figure (a) shows the waveform for the same program,
In this case, the waveform of the output of the low pass filter 30 (LPF 1) corresponding to the main tuner 8 and the waveform of the output of the low pass filter 32 (LPF 2) corresponding to the sub tuner 9 have the same or similar shape, and therefore each waveform is shaped. Circuit 31
The timings of the rising and falling edges of the zero crossing waves output from and 33 are the same. Therefore, the output of the phase comparison circuit 34 becomes almost low level and the output of the low pass filter 35 (LPF 3) also becomes low level, so that the identification signal becomes high level and the same program is detected.

On the other hand, in the case of different programs, the output waveforms of the low-pass filters LPF 1 and LPF 2 become different as shown in FIG.
The rising and falling timings of the zero crossing wave output from will not match. Therefore, the phase comparator 34
Output does not become low level and low pass filter 35 (LPF
Output becomes larger than the reference voltage E _t identification signal 3) is detected to be made different programs at a low level.

FIG. 3 shows a procedure of the above-mentioned network station search processing in the network receiving apparatus of FIG. In the process of the figure, first, the main tuner if receiving listening at a frequency f _main, storing frequency f _main in the receiving listening as a network station frequency f _{net Non.} Then, and the variable i "0", to calculate the _f o + i · _Δf as the reception frequency f _sub of the sub-tuner. Here, f _o is the lower limit frequency of the reception band, Delta] f is the frequency interval of the broadcast station. Then, it is determined whether or not the reception frequency f _{sub of the sub} tuner and the reception frequency f _{main of the} main tuner are equal, and if they are not equal, the sub tuner is selected to the frequency f _sub calculated as described above and reception is performed. Then, if the electric field strength of the received radio wave is greater than the predetermined value, whether of determining whether or phase error detection output identification signal output from the voltage comparator 36 is high is less than the reference value E _t The process of determining is performed. The phase error detection output, thereby terminating the process by setting the sub-tuner frequency f _sub as a network broadcast station frequency equal to or less than the reference value E _t. In the above process, the phase error detection output is output at the reference value E _{t at} a frequency different from that of the main tuner.
If it is less than or equal to and the broadcasting station whose electric field strength is larger than a predetermined value is not detected, the value of i is sequentially incremented.
The same processing is performed until the value of becomes equal to or larger than the maximum value M. Here, M is the maximum value of i, in which the upper limit frequency of the reception band is f _{o +} M · Δf, the aforementioned processing, the search tuning a predetermined reception band by sub-tuner 9 while, the phase error detection output and the field strength is less than the reference value E _t stores the frequency of greater than a predetermined value the broadcasting station. If at least one of these conditions is not satisfied, the search tuning process is continued. If a network station and a broadcasting station of the same program are detected by such processing, the main tuner 8 switches to a new network station when the electric field strength of the broadcasting station being listened to decreases. I do. In this case, in addition to the method of switching the tuning frequency of the main tuner 8 to the frequency of the stored broadcasting station of the same program, the sub tuner 9 performs the search tuning to detect a broadcasting station satisfying the above two conditions. At that time, the sub tuner 9 is fixed to the frequency of the broadcasting station and the output from the sub tuner 9 is switched to the power amplifier 10 when the electric field strength of the broadcasting station being listened to by the main tuner becomes small. It is also possible.

〔The invention's effect〕

As described above, according to the present invention, the switching of the channel selection is performed by judging the identity of the broadcast contents of a plurality of network broadcasting stations, so that the electric field strength at the end of the service area of the listening broadcasting station, etc. With respect to the deterioration of the reception quality due to the deterioration of the broadcasting station, the broadcasting station automatically switches to another broadcasting station of the same program and the same program, and the continuous listening of the same program can be accurately performed. Further, it is possible to cope with the establishment of a new network broadcasting station, etc., and it becomes possible to accurately and continuously listen to the same program by excluding local programs etc. of the network broadcasting station. Further, even during the search for a network station that is broadcasting the same program, it is not necessary to interrupt the listening and listening, and it is possible to switch the broadcasting station selection quickly. Furthermore, the process of identifying the same program is performed at extremely high speed, and the identification circuit can be simplified.

That is, according to the present invention, since the instantaneous phases of the audio output signals of the first and second tuner sections are compared to determine the identity of the broadcast contents, the audio output signals of the first and second tuner sections are compared. It is not affected by level fluctuations, and therefore is not affected by differences in received electric field strength due to distance differences with each broadcasting station, variations in the first and second tuner units, external factors, etc. In addition, since it is possible to detect the identity of the broadcast content, and since it does not require a complicated calculation as in the past, the time required for the detection can be shortened and the configuration can be simplified.

[Brief description of drawings]

FIG. 1 is a block circuit diagram showing an outline of a network receiving apparatus according to the present invention, FIGS. 2 (a) and 2 (b) are waveform diagrams showing signals of respective parts of the apparatus of FIG. 1, and FIG. 3 is FIG. FIG. 4 is a flow chart showing a network station search processing procedure in this device, and FIG. 4 is a block circuit diagram showing a configuration of a conventional network receiving device. 1, 7: Antenna, 2: Tuner, 3, 10: Power Amplifier, 4, 11: Speaker, 5, 16: Processor, 6: Network Frequency Memory, 8: Main Tuner, 9: Sub Tuner, 17: Tuning Operation Switch and display, 30, 32, 35: Low-pass filter, 31, 33: Waveform shaping circuit, 34: Phase comparison circuit, 36: Voltage comparator.

Claims (3)

[Claims] 1. A first tuner unit comprising a first tuner unit, a second tuner unit, a comparing unit for comparing the received contents of the first tuner unit and the second tuner unit, and a control unit. The second broadcast station that has the same contents as the first broadcast station that is receiving
And a low-pass filter having the same characteristics for removing high-frequency components of the audio output signals of the first and second tuner units, and the low-pass filter. A waveform shaping circuit for converting each output of the above into a zero crossing wave, a phase comparator for detecting the phase difference of each output of the waveform shaping circuit, and a signal obtained by smoothing the output of the phase comparator and a reference voltage are compared. And a comparator for deriving an identification signal indicating the identity of the broadcast content, and comparing the instantaneous phases of the audio output signals of the first and second tuner units to determine the identity of the broadcast content. When the second broadcasting station is detected and the reception electric field strength of the first broadcasting station becomes smaller than a predetermined value, the control unit detects the second broadcasting station and Instead, the second broadcast station performs reception. 2. The control section includes storage means for storing frequency information of the second broadcasting station, and when the reception electric field strength of the first broadcasting station becomes smaller than a predetermined value, the first tuner section. 2. The network receiving apparatus according to claim 1, wherein the reception frequency of the second broadcasting station is switched to the frequency of the second broadcasting station stored in the storage means to receive the second broadcasting station. 3. The control section holds the second tuner section in a state of being tuned to the second broadcasting station, and when the reception electric field strength of the first broadcasting station becomes smaller than a predetermined value, The network receiving device according to claim 1, wherein reception is continued at the tuner unit of No. 2.