JPH0677775A - Same program identification device - Google Patents

Abstract

PURPOSE:To surely recognize a same program. CONSTITUTION:When a zero cross point is detected from a demodulation signal from a main tuner section A and a sub tuner section B, while a noise component is detected by a noise detection section 15, the detection of the zero cross point of a same program identification circuit 10 is stopped. Thus, even when external noise is generated, since the detection of the zero cross point is ensured, a same program is surely identified.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for identifying the same program in a tuner, and more particularly to an apparatus for identifying the same program which prevents malfunctions in identifying the same program due to external noise such as ignition noise. .

[0002]

2. Description of the Related Art An identical program discriminating apparatus divides demodulated outputs of a pair of tuners capable of automatic channel selection into frequency components, and discriminates the identities of programs based on frequency components of two or more waves. It is a thing.

As a result, even if the service area of the broadcasting station changes and the reception condition deteriorates while the vehicle is running, for example, switching to a station with a good reception condition is automatically performed. Therefore, the same program can be continuously listened to without annoying the driver's hand.

FIG. 1 shows an example of the same program discriminating circuit provided in the AM tuner. AM radio waves taken in from the antenna 1 are fed by the RF amplifying sections 2 and 3 of the main tuner section A and the sub tuner section B. Tuned and amplified VCO1
It is converted to an intermediate frequency by passing through a MIX stage 17 controlled by 6. Next, after passing through the filters 4 and 5, the signals are amplified by the IF amplifiers 6 and 7. Further, the amplified intermediate frequency IF is detected by the detection unit 8,
After being demodulated by 9, the signal is output through the switching circuit 11.

The demodulated outputs from the detection units 8 and 9 are
After the pass band is limited by BPFs (not shown) provided in the same program demodulation circuit 10, the zero-cross point is detected by the zero-cross detector.

The control unit 12 takes in the signal level which is the detection output from the level detection units 13 and 14, and when the detection output of the level detection unit 13 falls below a predetermined level, it switches the switching circuit 11 to the detection unit 9. Switch to the side that captures the demodulation output.

Here, the principle of zero-cross count detection by the above-mentioned zero-cross detector will be described with reference to FIG.

That is, when the BPF output as shown in the figure is taken into the zero-cross detector, a pulse signal inverted at the black points in the figure is output. The control unit (microcomputer) 12 counts the rising and falling edges of these pulse signals. In the example of the figure, the count number is 6. Therefore, the detection units 8 and 9
When the respective count values of the demodulation outputs of No. 1 and No. 2 match, it is possible to recognize that they are the same program. The shaded area in the figure is the hysteresis area (dead zone).

Further, such recognition of whether or not they are the same program is performed according to the flow shown in FIG. 3, for example.

That is, when the recognition operation is started, the flag of the zero cross comparator output in the control unit 12 is set to, for example, "0" (step 301). When the set flag changes to "1" (step 302), the change is counted (step 3).
03).

In this way, the count result is output by sequentially counting the changes in the flags within the predetermined period (steps 304 and 305). The count result is output for each of the main tuner unit A and the sub-tuner unit B, and when they match, the received program of the sub-tuner unit B matches the received program of the main-tuner unit A. Is recognized.

[0012]

By the way, in general, AM
The noise in the broadcast wave includes all frequency components in a wide frequency range, and this is uniformly distributed in the AM broadcast wave.

Such AM broadcast waves are filtered by filters 4, 5
A predetermined band is cut by and is amplified by the IF amplifiers 6 and 7, and then detected by the detectors 8 and 9. However, the detection output may include ignition noise that cannot be separated and removed.

Therefore, in the above-mentioned conventional zero-cross count detection method, if external noise is superimposed on the demodulated signal which is the detection output when the silent state continues when recognizing the same program or when the modulation is shallow, Since this external noise also causes the count up, the count values of the demodulation outputs of the detectors 8 and 9 match even though the received program by the main tuner unit A and the received program by the sub tuner unit B are different. In some cases, different programs may be identified as the same.

The present invention has been made in consideration of such a situation, and provides an identical program identifying device capable of surely recognizing an identical program by preventing erroneous counting due to external noise or the like. With the goal.

[0016]

According to the present invention, a program received by a sub tuner unit is received by a main tuner unit by comparing a demodulated signal from the main tuner unit with a demodulated signal from a sub tuner unit. In the same program discriminating apparatus for discriminating whether or not it coincides with a program, noise detecting means for detecting a noise component from an amplified output of an intermediate frequency amplification stage of at least one of the main tuner section and the sub tuner section, and the main tuner. Section and a zero cross point detecting means for detecting a zero cross point from the demodulated signal from the sub tuner section, and a zero cross for stopping the detection of the zero cross point with respect to the zero cross point detecting means during a period when a noise component is detected by the noise detecting means. Point detection control means and the zero cross point Based on the detection result by preparative detecting means, characterized by comprising a program identification determination means for determining the identity of the received program.

Further, according to the present invention, by comparing the demodulated signal from the main tuner unit with the demodulated signal from the sub tuner unit, the program received by the sub tuner unit matches the program received by the main tuner unit. In the same program discriminating apparatus for discriminating whether or not the signal level strength detecting means for detecting the strength of the received signal level from the amplified output of the intermediate frequency amplifying stage of at least one of the main tuner section and the sub tuner section, and the main Based on the detection result by the zero cross point detecting means for detecting a zero cross point from the demodulated signal from the tuner section and the sub tuner section, and the signal level strength detecting means, the dead band width at the time of detecting the zero cross point by the zero cross point detecting means is set. Dead zone that controls to widen as the electric field becomes weaker And width control means, based on a detection result by the zero-cross point detecting means, characterized by comprising a program identification determination means for determining the identity of the received program.

Further, the present invention compares the demodulated signal from the main tuner section with the demodulated signal from the sub-tuner section so that the program received by the sub-tuner section matches the program received by the main-tuner section. In the same program discriminating device for discriminating whether or not, a noise removing unit provided on an output side of at least one of the main tuner unit and the sub tuner unit for eliminating noise, and the main tuner unit and the sub tuner unit It is characterized by comprising a zero cross point detecting means for detecting a zero cross point from the demodulated signal from and a program identity judging means for judging the identity of the received programs based on the detection result by the zero cross point detecting means.

[0019]

In the same program discriminating apparatus of the present invention, when the zero cross point is detected from the demodulated signals from the main tuner section and the sub tuner section, the zero cross point detecting section is operated while the noise component is being detected by the noise detecting section. Stopped the detection of the zero cross point.

As a result, even if external noise occurs, the zero-cross points are not counted up due to the external noise, and only the zero-cross points of the demodulated signal are reliably detected. Therefore, the same program can be identified with certainty. Become.

Further, in the same program identifying apparatus of the present invention, when the zero cross point is detected from the demodulated signals from the main tuner section and the sub tuner section, the width of the dead band at the time of detecting the zero cross point by the zero cross point detecting means is set to a weak electric field. I made it wider as I became.

As a result, even when external noise or the like is generated especially when the silent state continues,
The zero-cross point is not counted up due to the noise signal, and erroneous recognition in identifying the same program is prevented.

Further, in the same program identifying apparatus of the present invention, when the zero cross point is detected from the demodulated signals from the main tuner section and the sub tuner section, the demodulated signal which is the output of at least one of the main tuner section and the sub tuner section is detected. On the other hand, the noise was removed.

As a result, the accuracy of the count value of the zero cross points of the demodulated signal of the detection unit 8 is improved, so that erroneous recognition in identifying the same program can be prevented.

[0025]

Embodiments of the present invention will be described below in detail with reference to the drawings. In the drawings described below, the same parts as those in FIG. 1 are designated by the same reference numerals, and overlapping description will be omitted.

FIG. 4 shows the same program identifying apparatus of the present invention as an AM.
This is an example of application to a tuner, in which the AM radio wave taken in from the antenna 1 is the main tuner unit A
And the RF amplification units 2 and 3 of the sub tuner unit B and the VCO 16
The signal is output via the MIX stage 17, the filters 4, 5, the IF amplifiers 6, 7, the detectors 8, 9 and the switching circuit 11, which are controlled by.

The demodulated outputs from the respective detectors 8 and 9 are taken into the same program discriminating circuit 10 to detect the zero cross points.

The control unit 12 receives the detection result of the same program demodulation circuit 10 and the signal level detection results of the level detection units 13 and 14.

The sub-tuner section B side is provided with a noise detection section 14 for detecting a noise component contained in the intermediate frequency IF amplified by the IF amplification section 7. The control unit 12 takes in the detection result of the noise detection unit 14, and when the noise is generated, stops the same program identification circuit 10 from counting the zero cross points during the noise generation period.

FIG. 5 shows the internal structure of the same program demodulation circuit 10. The zero-cross detectors (ZCD) 10a to 10d detect zero-crosses of the demodulated signals of the detectors 8 and 9, respectively. Each zero-cross detector 10a-10
The detection results of the zero cross by d are counters 10e to 1
When counted by 0h, for example, exclusive NOR
Matching determination circuit 1 composed of circuits
It is taken into 0i and 10j. Each match determination circuit 10i,
10j is a zero-cross detector 10a, 10b and 10
When the detection results from c and 10d match, a pulse signal indicating the match is output. The result determination unit 10k determines the result based on the pulse signals from the matching determination circuits 10i and 10j, and outputs this determination result to the control unit 12.

An operation timing pulse signal is given from the control unit 12 to each of the counters 10e to 10h and each of the matching determination circuits 10i and 10j, and each of the counters 10e to 1e.
0h and the count period and the determination period by the coincidence determination circuits 10i and 10j are controlled by the operation timing pulse signal.

Next, the operation of the same program identifying apparatus having such a configuration will be described with reference to FIGS. 5, 6 and 7.

First, the flag of the zero cross comparator output which is the coincidence determination circuits 10i and 10j of the same program demodulation circuit 10 is set to, for example, "0" (step 60).
1). When the noise detection unit 14 detects noise (step 602), the flag is set again in (step 601). On the other hand, if no noise is detected, it is determined that the flag has changed (step 603), and if it has been determined that there is a change, the change is counted (step 604).

In this way, the count result is output by sequentially counting the changes of the flags within the predetermined period (steps 605 and 606).

Here, the zero cross points when the noise is not detected by the noise detecting section 15 are c, d, e and f, and the count value is 4, as shown in FIG. On the other hand, the zero cross points when noise occurs are a, b, c, d, e, and f, and the count value is 6. In addition, noise generation period g ~ h
If the zero-crossing count is simply stopped between and i to j, the zero-crossing points are c, d and f, and the count value is 3.

Therefore, from the above, i ~
Stopping the count between j will remove the normal zero-cross point, so i ~ before and after that zero-cross point
The level change of j is detected, and when there is a change in the level, the zero cross point is counted as a normal one.

FIG. 8 shows another embodiment in which the flow of FIG. 6 is changed. In this example, if noise is detected in (step 802), (step 801)
The state of the flag set by is maintained.

As described above, in these embodiments, when the zero cross point is detected from the demodulated signals from the main tuner unit A and the sub tuner unit B, the same program is detected while the noise component is detected by the noise detection unit 15. Since the detection of the zero cross point is stopped for the identification circuit 10, even if the external noise is generated, the zero cross point is not counted up due to the external noise, and only the detection of the zero cross point of the demodulated signal is surely performed. Therefore, it is possible to identify the same program surely.

FIG. 9 shows another embodiment in which the method of detecting a zero cross point in the same program identifying apparatus of FIG. 4 is changed, and in this embodiment, the dead zone x is set in accordance with the electric field strength of the signal level. By changing the interval, erroneous recognition of the same program due to pulse noise is prevented.

That is, FIG. 10A shows a noise waveform in a weak electric field, and FIG. 10B shows a noise waveform in a strong electric field.

As can be seen from these figures, as is clear from FIG. 9A, when the noise level is high, zero crosses are counted at the upper and lower boundaries of the dead zone x. On the other hand, as shown in FIG. 6B, in a strong electric field, the level of the noise waveform is small and the zero-cross count is not performed, so there is no problem.

Therefore, in this embodiment, the width of the dead zone x is a when the electric field is strong, b when the electric field is medium, and c when the electric field is weak (where a, b and c are a <b <c. There is).

Next, the operation of the zero cross count of this embodiment will be described with reference to FIG.

First, the control section 12 takes in the detection result of the signal level of the level detection section 14 of the sub tuner section B,
The signal level is judged (step 901). The determination of the signal level is performed by, for example, comparing the data indicating the strong, medium, and weak levels of the electric field written in a memory (not shown) in the control unit 12 with the detection result of the signal level of the level detection unit 14. .

As a result of the judgment, when the electric field strength is strong, the dead band x = a is set and the same program discriminating circuit 10 is caused to count the zero cross. When the electric field strength is medium or weak, the dead band x = b or c is set, and the same program identifying circuit 10 is caused to count zero crosses (steps 902 to 905).

At this time, the zero-cross counting is performed in parallel with the demodulated outputs of the detectors 8 and 9.

When such zero-cross count is carried out until the predetermined time is reached (step 906), it is judged whether or not the broadcast is the same broadcast (step 907). If the zero-cross count values for the demodulated outputs of the detectors 8 and 9 match, they are regarded as the same program (step 9).
08). On the other hand, if the zero-cross count values for the demodulated outputs of the detectors 8 and 9 do not match, the broadcast is different (step 909).

As described above, in this embodiment, when the zero cross point is detected from the demodulated signals from the main tuner unit A and the sub tuner unit B, the width x of the dead band at the time of detecting the zero cross point by the same program identifying circuit 10 is set. Since the width is made wider as the electric field becomes weaker, even if external noise is generated especially when the silence state continues, the zero cross point is not counted up by the noise signal and the same program is identified. False recognition in is prevented.

FIG. 11 shows another embodiment in which the configuration of the same program identifying apparatus of FIG. 4 is changed. In this embodiment, demodulation which is the detection output of the main tuner section A or the sub tuner section B is demodulated. Erroneous recognition of the program identity judgment is prevented by removing noise from at least one of the signals.

That is, as shown in the figure, a PNS (pulse noise reduction) 16 is provided on the output side of the detection section 8 of the main tuner section A. As a result, the demodulated signal from which noise has been removed is taken into the same program identification circuit 10.

As a result, when the same recognition is performed by the zero-cross method, different programs are made the same when noise appears in the demodulated signal as described above when the silent state continues. Since the noise is removed, the determination of the same recognition is not made unless the zero-cross count values of the two coincide with each other, so that the false recognition of the sameness determination is prevented.

As described above, in this embodiment, when the zero cross point is detected from the demodulated signals from the main tuner unit A and the sub tuner unit B, the detection which is the output of at least one of the main tuner unit A and the sub tuner unit B is performed. Since the noise is removed from the demodulated signal of the unit 8, the accuracy of the count value of the zero cross points of the demodulated signal of the detection unit 8 is improved, so that erroneous recognition in the identification of the same program is prevented.

[0053]

As described above, according to the same program identifying apparatus of the present invention, when the zero cross point is detected from the demodulated signals from the main tuner section and the sub tuner section, the noise component is detected by the noise detecting means. Since the zero cross point detection means is made to stop the detection of the zero cross point during the period during which the zero cross point of the demodulated signal is not counted up even if external noise is generated, the zero cross point is not counted up. Since only the detection is surely performed, the same program can be surely identified.

Further, in the same program identifying apparatus of the present invention, when the zero cross point is detected from the demodulated signals from the main tuner section and the sub tuner section, the width of the dead band at the time of detecting the zero cross point by the zero cross point detecting means is set to a weak electric field. However, even if external noise is generated, especially when the silent state continues, the zero cross point is not counted up due to the noise signal, and the same program is erroneously identified. It is possible to prevent recognition.

Further, in the same program identifying apparatus of the present invention, when the zero cross point is detected from the demodulated signals from the main tuner unit and the sub tuner unit, the demodulated signal which is the output of at least one of the main tuner unit and the sub tuner unit is detected. On the other hand, since the noise is removed, the detection unit 8
Since the accuracy of the count value of the zero-cross point of the demodulated signal is improved, it is possible to prevent erroneous recognition in identifying the same program.

[Brief description of drawings]

FIG. 1 is a block diagram showing an example of a conventional identical program identifying apparatus.

FIG. 2 is a diagram for explaining the principle of zero cross count recognition of the same program identifying apparatus of FIG.

FIG. 3 is a flowchart for explaining a zero-cross count recognition operation of the same program identifying apparatus of FIG.

FIG. 4 is a block diagram showing an embodiment in which the same program identifying apparatus of the present invention is applied to an AM tuner.

5 is a block diagram showing an internal configuration of the same program identifying circuit of FIG. 4. FIG.

6 is a flowchart for explaining the operation of the same program identifying apparatus of FIG.

FIG. 7 is a diagram for explaining the operation of the same program identifying apparatus of FIG.

8 is a flowchart showing another embodiment when the flow of FIG. 5 is changed.

9 is a diagram showing another embodiment in which the zero-cross count method of the same program identifying apparatus of FIG. 4 is changed.

FIG. 10 is a diagram for explaining a dead zone at the time of zero cross counting in FIG.

FIG. 11 is a diagram showing another embodiment when the configuration of the same program identifying apparatus in FIG. 4 is changed.

[Explanation of symbols]

 A Main tuner section B Sub-tuner section 1 Antenna 2,3 RF amplification section 4,5 Filter 6,7 IF amplification section 8,9 Detection section 10 Same program identification circuit 11 Switching circuit 12 Control section 13,14 Level detection section 15 Noise Detector 16 PNS (pulse noise reduction)

Front page continued (72) Inventor Kazuhiko Uchiyama 25 Nishimachi, Yamada, Kawagoe City, Saitama Prefecture 1 Pioneer Co., Ltd. Kawagoe Factory

Claims (3)

[Claims] 1. A comparison between the demodulated signal from the main tuner unit and the demodulated signal from the sub tuner unit determines whether the program received by the sub tuner unit matches the program received by the main tuner unit. In the same program discriminating device for discriminating, noise detecting means for detecting a noise component from an amplified output of at least one intermediate frequency amplification stage of the main tuner unit and the sub tuner unit, and demodulation from the main tuner unit and the sub tuner unit. Zero cross point detection means for detecting a zero cross point from a signal, a period during which a noise component is detected by the noise detection means, zero cross point detection control means for stopping the detection of the zero cross point for the zero cross point detection means, and the zero cross Detection by point detection means Based on the result, the same program identification apparatus characterized by comprising a program identification determination means for determining the identity of the received program. 2. A comparison between the demodulated signal from the main tuner unit and the demodulated signal from the sub tuner unit determines whether the program received by the sub tuner unit matches the program received by the main tuner unit. In the same program discriminating apparatus for discriminating, a signal level intensity detecting means for detecting intensity of a received signal level from an amplified output of at least one intermediate frequency amplification stage of the main tuner unit and the sub tuner unit, the main tuner unit and the sub unit Zero-cross point detection means for detecting a zero-cross point from the demodulated signal from the tuner section, based on the detection result by the signal level intensity detection means,
The dead band width control means for controlling the width of the dead band at the time of zero cross point detection by the zero cross point detection means to widen as the electric field becomes weaker, and the same received program based on the detection result by the zero cross point detection means. An identical program identifying apparatus comprising: a program identicalness determining means for determining the sex. 3. A comparison between the demodulated signal from the main tuner unit and the demodulated signal from the sub tuner unit determines whether the program received by the sub tuner unit matches the program received by the main tuner unit. In the same program discriminating device for discriminating, noise removing means for eliminating noise provided on an output side of at least one of the main tuner unit and the sub tuner unit, and demodulated signals from the main tuner unit and the sub tuner unit An identical program identifying device comprising: a zero cross point detecting means for detecting a zero cross point from the program; and a program identity judging means for judging the identity of received programs based on the detection result by the zero cross point detecting means.