JPH06233158A - Selector for received signal from antenna with less ghost of tv diversity - Google Patents

Abstract

PURPOSE:To provide satisfactory images by deciding/selecting the received signal with ghost wave small and improving the S/N of the received signal in the case of on-vehicle TV diversity. CONSTITUTION:The received signals are respectively detected, horizontal synchronizing signals are extracted by synchronizing circuits 7 and 8, and the signals are passed through a phase adjuster 9 and synthesized by a synthesizer 10. Similarly, respective phase adjusted signals performed subtraction processing by a subtracter 11 and impressed to a control signal generator 12, and a control signal is obtained. The subtraction processing signals are impressed to a sampling gate 13, a synthesized signal is impressed to a sampling gate 17, the sampling gates 13 and 17 are controlled by the control signal, positive and negative peak values are respectively detected by positive and negative peak hold circuits 14, 15, 18 and 19, and the magnitude relation of peak values is decided by comparators 16 and 20. The received signal with ghost wave small is decided by a ghost deciding circuit 21, the operation of a synthesizing processing selecting circuit 22 is controlled by the output, the synthesized signal and the subtracted signal are added or subtracted, and an output signal to a monitor 23 is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to TV diversity, and more particularly to a device for selecting a signal having a small ghost component in a received signal from a plurality of TV diversity antennas.

[0002]

2. Description of the Related Art FIG. 3 is a block diagram showing a configuration of a conventional example (input voltage determination switching circuit) of a receiving antenna selection circuit in a TV diversity system. As shown in FIG. 3, TV diversity generally includes a reception level comparator 3
The antenna select 32 is switched by the control signal from 7 to select one of the antennas 31-1 and 31-2,
The input signal is detected by the detection circuit 34 via the tuner 33 and output to the monitor 38.

The output of the detection circuit 34 is the reception level comparator 3
7, the synchronizing signal is taken out by the synchronizing circuit 35, is inputted to the control signal generator 36, and the receiving level comparator 37 is controlled by the output signal thereof to compare the input voltage with the vertical blanking period to obtain the maximum voltage. Select the antenna.

[0004]

The reception state of each antenna of a vehicle-mounted TV due to diversity often differs depending on the directivity of the antenna and the surrounding environment. However, since the above-mentioned conventional technique does not have a determination function for presence / absence of a ghost, there is a problem in that an antenna that can obtain the best image quality and that has a small ghost component is not always selected.

The present invention has been made in view of the above problems, and in vehicle-mounted TV diversity, a reception signal with a small ghost wave is determined / selected by utilizing the difference in the input ghost of each antenna, and the reception signal The object is to improve S / N and provide a good image.

[0006]

In order to achieve the above object, a receiving signal selection device from an antenna having a small ghost of TV diversity according to the present invention selects each received signal received by a plurality of antennas of TV diversity. Detection means for detecting and obtaining a detection signal, a synchronization component extraction means for obtaining a synchronization component signal from each detection signal, and addition processing of each detection signal whose phase is adjusted based on the synchronization component signal to obtain a ghost sum component signal Addition processing means,
Subtraction processing means for obtaining a ghost difference component signal by subtracting each detection signal whose phase is adjusted based on the synchronization component signal, and detecting the positive and negative peak levels of each of the addition signal and the subtraction signal and detecting the positive and negative peaks corresponding to each A positive / negative peak detecting means for obtaining a signal, and a peak difference component detecting means for obtaining a positive / negative peak difference component signal of each of the addition signal and the subtraction signal based on the positive / negative peak detection signal, and a positive / negative peak difference of each of the addition signal and the subtraction signal Based on the magnitude relationship of the component signal, based on the ghost component determination signal, the ghost component determination means to determine the extent of the influence of the ghost component contained in each received signal from each antenna to obtain the ghost component determination signal, Synthesis processing selection means for performing synthesis processing of the addition signal and the subtraction signal so as to obtain a reception signal less affected by the ghost component, Characterized in that it has.

[0007]

In order to achieve the above object, the apparatus for selecting a received signal from an antenna having a small ghost of TV diversity according to the present invention detects each received signal received by a plurality of antennas of TV diversity by the detection means. A detection signal is obtained, a synchronization component signal is obtained from each detection signal by the synchronization component extraction means, and each detection signal whose phase is adjusted based on the synchronization component signal is added by addition processing means to obtain a ghost sum component signal. Then, the subtraction processing means subtracts the respective detection signals whose phases have been adjusted based on the synchronization component signal to obtain a ghost difference component signal, and the positive / negative peak detection means detects the positive / negative peak levels of the addition signal and the subtraction signal. Then, the positive and negative peak detection signals corresponding to each are obtained and the positive and negative peak detection signals are detected by the peak difference component detection means. Based on the addition signal to obtain each of the positive and negative peak difference component signal of the subtraction signal. Then, the ghost component determination means determines the degree of influence of the ghost component included in each received signal from each antenna based on the magnitude relation between the positive and negative peak difference component signals of the addition signal and the subtraction signal, and determines the ghost component. Get the decision signal,
Based on the ghost component determination signal, the synthesizing process selecting unit synthesizes the addition signal and the subtraction signal so as to obtain a reception signal less affected by the ghost component.

[0008]

1 is a block diagram of a configuration example of a device for selecting a received signal from an antenna with little ghost of TV diversity according to the present invention, and FIG. 2 is a determination rule based on the magnitude of a ghost wave and a signal after subtraction processing. FIG.

In FIG. 1, 1 and 2 are receiving antennas, 3 and 4 are tuners, 5 and 6 are detectors, 7 and 8 are synchronizing circuits, which correspond to synchronizing component extracting means, and 9 is a phase adjuster and 10 Is an adder, 11 is a subtractor, 12 is a control signal generator, 13, 17
Is a sampling gate, 14 and 18 are positive peak hold circuits, 15 and 19 are negative peak hold circuits, 1
Reference numerals 6 and 20 are comparators, which correspond to peak difference component detection means, 21 is a ghost determination circuit, 22 is a combination processing selection circuit, and 23 is a monitor. In addition, the control signal generator 1
2, the sampling gates 13 and 17, the positive peak hold circuits 14 and 18, and the negative peak hold circuits 15 and 19 constitute positive and negative peak detection means.

In FIG. 1, each antenna 1, 2 has a tuner 3,
4. The detectors 5 and 6 are connected to detect the input signals from the antennas 1 and 2, respectively. The horizontal synchronizing signals are extracted from the detected video signals by the synchronizing circuits 7 and 8, the phase is adjusted by the phase adjuster 9, and the video signals from the antennas 1 and 2 are added by the adder 10.

The combined signal is 2 against random noise.
The S / N is improved at a rate of ^{1/2 (1/2)} . Similarly, the subtracter 11 performs a subtraction process on each video signal whose phase is adjusted by the phase adjuster 9. Furthermore, the signal whose phase has been adjusted by the phase adjuster 9 is added to the control signal generator 12 to obtain the control signals for the sampling gates 13 and 17.

Here, the video signal from the antenna 1 is X +
If the video signal from Y and the antenna 2 is X + Y '(where X: original signal, Y, Y': ghost wave), the subtractor 11
The signal after the subtraction process by YY becomes YY ', and the adder 10
The resulting composite signal is 2X + Y + Y '. Here, the signal YY ′ after the subtraction processing is shown in FIG.

The signal YY 'is sampled by the sampling gate 13
, The combined signal 2X + Y + Y ′ is supplied to the sampling gate 17
In addition, the control signal from the control signal generator 12 controls the respective sampling gates 13 and 17.

From the signal YY 'sampled by the sampling gate 13, a positive peak hold circuit 14 detects a positive peak value, a negative peak hold circuit 15 detects a negative peak value, and a comparator 16 compares the peak values. And a determination result (signal) Δy is obtained. Where Δy =
Positive peak value-negative peak value.

Similarly, from the combined signal 2X + Y + Y 'sampled by the sampling gate 17, the positive peak hold circuit 18 detects a positive peak value, the negative peak hold circuit 19 detects a negative peak value, and the comparator 20 detects the peak value. Judgment of magnitude relationship, judgment result (signal) Δy '
To get Here, Δy ′ = positive peak value−negative peak value.

The ghost wave input to the antennas 1 and 2 is judged from the positive and negative signs of Δy and Δy ', and the ghost judgment circuit 21 judges the received signal from the antenna having a small ghost wave according to the judgment pattern shown in FIG. , Ghost judgment circuit 2
The output of 1 controls the operation of the synthesis processing selection circuit 22.

The patterns (a) to (d) in the judgment pattern of FIG. 2 are cases where the ghost signal Y '<Y is judged, and the patterns (e) to (h) are the ghost signal Y <.
This is the case of determining Y '.

In the patterns (a) and (d), ΔY
Y '<Y when <0, Δy ′ <0, and Y ′ when ΔY> 0 and Δy ′> 0 in patterns (b) and (c).
<Y and ΔY> 0, Δy ′ in patterns (e) and (g)
When <0, Y <Y ', and in patterns (f) and (h), when ΔY <0, Δy'> 0, Y <Y 'is determined (that is, Δy, Δy'. Have the same sign, Y '<Y, and if they have different signs, Y <Y').

The synthesizing process selection circuit 22 is controlled by the ghost determining circuit 21 to synthesize the synthetic signal 2X + Y + Y 'and the subtraction signal Y.
-Y 'is added (2X + 2Y) or subtracted (2X + 2Y)
Y ') to obtain a video output signal to the monitor 23. The video output signal obtained by the synthesis processing selection circuit 22 is the signal with the smaller ghost out of the signals received from the antennas 1 and 2, and the S / N is improved as described above.

[0020]

As described above, according to the receiving signal selecting apparatus of the present invention having a small ghost of TV diversity, the S / N ratio of the in-vehicle TV receiving signal is improved and the receiving signal from the antenna having a small ghost wave is received. Can be selected, so that a good image can be provided.

[Brief description of drawings]

FIG. 1 is a block diagram of a configuration example of a device for selecting a received signal from an antenna with little ghost of TV diversity according to the present invention.

FIG. 2 is an explanatory diagram of a determination rule based on the magnitude of a ghost wave and a signal after subtraction processing.

FIG. 3 is a block diagram showing a configuration of a conventional example (input voltage determination switching circuit) of a receiving antenna selection circuit in the TV diversity system.

[Explanation of symbols]

1, 2 Receive antennas 3, 4 Tuners 5, 6 Detectors (detection means) 7, 8 Synchronous circuits (synchronous component extraction means) 10 Adders (addition processing means) 11 Subtractors (subtraction processing means) 12 Control signal generators (Positive / negative peak detection means) 13,17 Sampling gate (positive / negative peak detection means) 14,18 Positive peak hold circuit (positive / negative peak detection means) 15,19 Negative peak hold circuit (positive / negative peak detection means) 16,20 Comparator (peak Difference component detection means) 21 ghost determination circuit (ghost component determination means) 22 synthesis processing selection circuit (synthesis processing selection means)

Claims (1)

[Claims] 1. A detection means for detecting each reception signal received by a plurality of antennas of TV diversity and obtaining a detection signal, a synchronization component extraction means for obtaining a synchronization component signal from each detection signal, and the synchronization component signal. The addition processing means for obtaining the ghost sum component signal by adding the respective detection signals whose phase is adjusted based on the above, and the ghost difference component signal by subtracting the respective detection signals whose phases are adjusted based on the synchronous component signal. Subtraction processing means to obtain, the addition signal, positive and negative peak detection means to obtain the positive and negative peak detection signal corresponding to each positive and negative peak level of the subtraction signal, based on the positive and negative peak detection signal, the addition signal, Peak difference component detecting means for obtaining respective positive and negative peak difference component signals of the subtraction signal, and the addition signal and the subtraction signal. Based on the magnitude relationship of the respective positive and negative peak difference component signal, a ghost component determination means for determining the extent of the influence of the ghost component contained in each received signal from each antenna to obtain a ghost component determination signal, Based on a ghost component determination signal, a combining process selecting means for combining the addition signal and the subtraction signal so as to obtain a reception signal less influenced by the ghost component, and a TV diversity of A device for selecting the received signal from the antenna with less ghost.