JP3221022B2 - Diversity receiver - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention provides a plurality of receiving antennas, and selects the best one of the antenna output signals obtained from each of the receiving antennas, and receives a signal based on the selected antenna output signal. The present invention relates to a diversity receiver for forming a signal.

[0002]

2. Description of the Related Art In a television broadcast receiving system mounted on a vehicle, a receiving state is often taken under the condition that a receiving electric field state frequently changes.
Usually, a diversity receiving method in which a plurality of receiving antennas are provided is employed. A television broadcast receiving system mounted on a vehicle adopting such a diversity receiving method constitutes a diversity receiving device.In such a diversity receiving device, for example, the middle left and right in a cabin forming unit of a vehicle is used. A total of four receiving antennas are provided in each of the part and the rear left and right parts, and four receiving antennas respectively obtained from the four receiving antennas in a specific period such as a vertical blanking period in a received television broadcast signal. By comparing the levels of the received output signals formed by the received signal processing unit based on each of the antenna output signals, the received output signal having the highest level among the four antenna output signals is formed. Will be selected, and will be selected in a period other than the specified period thereafter. The antenna output signal is supplied to the reception signal processing unit, whereby the configuration reproduced sound reproduced image and its associated on the basis of the received output signal obtained from the reception signal processing unit is obtained is taken.

When a reception output signal having the highest level among the four antenna output signals is selected, the reception output signal is obtained through each of the four antenna connection terminals. A signal sampling operation is performed on the antenna output signal, and the antenna output signal extracted by the signal sampling operation is supplied to the reception signal processing unit. The levels of the reception output signals sequentially formed by the reception signal processing section are compared with each other.

[0004]

As described above, the signal sampling operation is performed on a plurality of antenna output signals, and a reception output signal having the highest level among the plurality of antenna output signals is formed. Is selected, the received output signal based on the selected antenna output signal is provided for the reproduction of the image and the sound, the received output signal based on each of the plurality of antenna output signals Are based on the assumption that the one with the highest level will be the best. However, the one having the maximum level among the received output signals based on each of the plurality of antenna output signals may be the best in terms of quality in consideration of the S / N ratio (noise-to-signal ratio) and the like. It is true that there are many, but on the other hand, the one having the maximum level among the plurality of received output signals based on the plurality of antenna output signals is not always the best in terms of quality The probability of occurrence is not low.

[0005] For example, when a reception output signal based on each of a plurality of antenna output signals includes a ghost signal component, the level of each reception output signal is regarded as the entire level including the ghost signal component. The received output signal having a level actually contains a high-level ghost signal component, and the level of the originally desired signal component is small, and thus is not the best in quality. The situation occurs. Then, the reception output signal including such a ghost signal component is subjected to a signal sampling operation for a plurality of antenna output signals as described above, and among the plurality of antenna output signals,
The reception output signal based on the selected antenna output signal is obtained in a configuration where the reception output signal based on the selected antenna output signal is provided for the reproduction of the image and the sound, under the condition that the reception output signal having the highest level is to be formed. In the case, of the plurality of reception output signals based on the plurality of antenna output signals,
It is no longer possible to select the best quality in terms of quality and to reproduce the image and sound, so that only a reproduced image with inferior image quality and a reproduced sound with inferior sound quality can be obtained.

In view of the above, the present invention is provided with a plurality of receiving antennas, and selectively extracts a plurality of antenna output signals obtained from the plurality of receiving antennas within a specific period in a predetermined short period. A signal sampling operation is performed, and the antenna output signal extracted by the signal sampling operation is supplied to the reception signal processing unit, and based on the result of the evaluation of the reception output signal sequentially formed by the reception signal processing unit based on the antenna output signal. Thus, one of the plurality of antenna output signals is selected, and in a period other than a specific period thereafter, under the assumption that the formation of the reception output signal based on the selected antenna output signal is performed continuously, Regardless of whether or not the received output signal based on each of the plurality of antenna output signals includes a ghost signal component Reception output signal based on the selected antenna output signal and to provide a diversity receiving apparatus probability would have significantly enhanced which is what the best in terms of quality.

[0007]

In order to achieve the above object, a diversity receiving apparatus according to the present invention comprises a plurality of antenna connection terminals to which respective receiving antennas are connected, and a plurality of antenna connection terminals obtained through a plurality of antenna connection terminals. An antenna output signal selecting unit for selecting and extracting one of the antenna output signals, and receiving the antenna output signal selected by the antenna output signal selecting unit to form a reception output signal based on the antenna output signal a signal processing unit, and a ghost component separating unit taken out by separating the ghost signal components contained in the received output signal from the reception signal processing section, ghost
Of the ghost signal component extracted by the
A ghost component level detector for detecting a bell, and a ghost
Based on the ghost signal component extracted by the component separation unit.
Ghost component number detector that detects the number of ghosts
And, in a specific period, the antenna output signal selection unit,
An antenna output signal sampling control section for performing a signal sampling operation for sequentially extracting each of a plurality of antenna output signals obtained through a plurality of antenna connection terminals for a predetermined short period, and an antenna for a specific period
Antenna output signals sequentially extracted by the output signal selector
A level detector for detecting the level of each signal, and a level detector.
Antenna output based on the level detected by the output
Of the antenna output signal sequentially taken out by the signal selector.
Of which has at least the maximum level and the second
Signals with the highest level are sent to the maximum level signal and
Ghost component level detection
Detected by the output part and ghost component number detection part respectively
Ghost signal component level and maximum level signal
Level signal evaluated based on the number of ghosts and ghosts
Quality is above a predetermined standard,
Is the ghost component, although not higher than the preset reference
Level detection unit and ghost component number detection unit detect
Of the ghost signal component of the output second level signal
Second rank evaluated based on level and number of ghosts
When the signal level is higher than the
Signal to be supplied to the
The quality of the signal is not higher than the preset standard, and
When the quality of the second-level signal is not higher than
A signal selection unit for selecting a signal to be supplied to the reception signal processing unit, the specific time period other than a period, to output the signal that was selected by the signal selecting unit to the antenna output signal selecting section <br/> up e Bei received signal switching controller to perform the operation, the
It is composed.

[0008]

In the diversity receiving apparatus according to the present invention having such a configuration, the antenna output signal selecting unit performs the signal sampling operation by the antenna output signal selecting unit during a period other than a specific period during which the signal sampling operation is performed. As one of the plurality of extracted antenna output signals, the respective levels of the reception output signals sequentially obtained from the reception signal processing unit are compared with each other according to the antenna output signals sequentially extracted by the signal sampling operation. Of the comparison result and the received output signal.
Of ghost signal component and number of ghosts contained in
Forming a reception output signal deemed to be of the highest quality based on the evaluation result of the ghost state based on
That the determined antenna output signal is selected as. Therefore, not only when the received output signal based on each of the plurality of antenna output signals does not include a ghost signal component, but also when the received output signal includes a ghost signal component, the received output signal based on the selected antenna output signal is used. The probability that the signal will be the best in quality will be significantly increased.

[0009]

FIG. 1 shows an example of a diversity receiving apparatus according to the present invention. This example constitutes an on-vehicle television receiver. In the example shown in FIG. 1, for example, four antenna connection terminals 11A, 11B, 11C, and 11D provided respectively in the middle left and right portions and the rear left and right portions in the cabin forming portion of the vehicle are provided. The receiving antennas 12A, 12B, 12C and 12D are connected to the antenna connection terminals 11A to 11D, respectively.

[0010] The television broadcast signal is received by the receiving antenna 12.
The antenna output signals SA, SB, SC, and SD respectively obtained through the antenna connection terminals 11A to 11D by being received by the antennas A to 12D are connected to the capacitor 14A.
To the switching diode 15A through the capacitor 14B to the switching diode 15B,
Switching diode 1 through capacitor 14C
5C and through a capacitor 14D to a switching diode 15D. Switching
As described later, any one of the diodes 15A to 15D is turned on, so that the antenna output signal SA, SB, SC, or SD outputs the switching diode 15A, 15B, 15C, or 1
The signal is supplied to the tuner 31 constituting the received signal processing unit 30 through 5D and further through the capacitor 16.

The tuner 31 performs high-frequency amplification and frequency conversion on the antenna output signal SA, SB, SC or SD. The tuner 31 outputs a video intermediate frequency signal SVI based on the antenna output signal SA, SB, SC or SD. Is obtained, which is the intermediate frequency amplification unit 3
2 is supplied. Then, the video intermediate frequency signal SVI amplified by the intermediate frequency amplification unit 32 is supplied to the video detection unit 33, and the video detection unit 33 demodulates the video intermediate frequency signal SVI to obtain the video signal VD. The video signal VD obtained from the video detection unit 33 is amplified by the video amplification unit 34, further power-amplified by the output amplification unit 35, and supplied to the cathode ray tube 36.
A reproduced image based on the video signal VD can be obtained on the display screen portion of.

From the intermediate frequency amplifier 32, an audio intermediate frequency signal SAI separated from the video intermediate frequency signal SVI is also obtained, and supplied to the audio intermediate frequency amplifier 37. Then, the audio intermediate frequency signal SAI amplified by the audio intermediate frequency amplification unit 37 is supplied to the audio detection unit 38, and the audio detection unit 38 demodulates the audio intermediate frequency signal SAI to obtain an audio signal AU. The audio signal AU obtained from the audio detection unit 38 is amplified in the audio amplification unit 39 and supplied to the speaker 40, and the speaker 40 obtains a reproduced audio based on the audio signal AU.

The video signal VD obtained from the video detection unit 33 is supplied to a synchronization separation unit 41 and a video signal sampling unit 4.
2, and also to the ghost component separation unit 58. In the synchronization separation section 41, the vertical synchronization signal SV and the horizontal synchronization signal SH in the video signal VD are separated, and they are transmitted from the synchronization separation section 41.

The video signal V sent from the sync separation section 41
The vertical synchronization signal SV and the horizontal synchronization signal SH in D are supplied to the antenna output signal sampling controller 46. The antenna output signal sampling controller 46 controls the video signal VD based on the vertical synchronization signal SV and the horizontal synchronization signal SH.
During the vertical blanking period, a specific period, for example, a period corresponding to an equivalent pulse following the vertical synchronization signal SV is detected, and a specific period sequentially detected during each vertical blanking period in the video signal VD is detected. Or the control signal SS is supplied to the diode drive signal forming unit 47 during a specific period detected during a vertical blanking period at every predetermined period that is an integral multiple of the vertical period of the video signal VD.

The diode drive signal forming section 47 has four output terminals, each of which is connected to a choke coil 4.
8, 49, 50 and 51 are connected to the respective anodes of the switching diodes 15A, 15B, 15C and 15D. The cathodes of the switching diodes 15A to 15D are commonly connected and grounded via a choke coil 52 and a parallel connection of a resistor 53 and a capacitor 54. Then, in response to the control signal SS from the antenna output signal sampling control unit 46, the diode drive signal forming unit 47 detects the vertical position within the vertical blanking period in the video signal VD detected by the antenna output signal sampling control unit 46. In a specific period which is a period corresponding to the equivalent pulse following the synchronization signal SV, the switching diodes 15A to 15D are turned on from the four output terminals to the respective anodes of the switching diodes 15A to 15D. An operation of supplying the drive signals C1, C2, C3 and C4 sequentially for a predetermined short period of, for example, several microseconds is performed.

Therefore, during a specific period detected by the antenna output signal sampling control section 46, the switching diodes 15A, 15B, 15C and 15C
D are sequentially turned on for a predetermined short period,
Thereby, the antenna output signals SA to SD are, for example,
Switching is performed sequentially for a predetermined short period of several microseconds.
A signal sampling operation taken out through the diodes 15A, 15B, 15C and 15D is performed, and a state is obtained in which the taken out antenna output signals SA to SD are supplied to the tuner 31. Therefore, the switching diodes 15A to 15D and the diode drive signal forming unit 47 form an antenna output signal selecting unit, and are included in each vertical blanking period of the video signal VD or the vertical cycle of the video signal VD. In a vertical blanking period for each predetermined cycle of an integral multiple of the period, for example, in a specific period that is a period corresponding to an equivalent pulse following the vertical synchronization signal SV, the video detection unit 33
The video signal VD based on the antenna output signal SA, the video signal VD based on the antenna output signal SB, the video signal VD based on the antenna output signal SC, and the antenna output signal S
The video signal VD based on D is sequentially transmitted for a predetermined short period.

The video signal VD and the antenna output signal SB based on the antenna output signal SA from the video detector 33
The video signal VD based on the antenna output signal SC, and the video signal VD based on the antenna output signal SD,
The horizontal synchronizing signal SH is supplied to the video signal sampling unit 42 to which the horizontal synchronizing signal SH is supplied. The control signal SS transmitted from the antenna output signal sampling control unit 46 is also supplied to the video signal sampling unit 42, and the video signal sampling unit 42 synchronizes with the transmission of the control signal SS from the antenna output signal sampling control unit 46. Signal V based on the antenna output signal SA supplied from the video detector 33
D, a video signal VD based on the antenna output signal SC, a video signal VD based on the antenna output signal SC, and a video signal VD based on the antenna output signal SD are sequentially extracted and supplied to the video signal level detection unit 43.

The video signal level detector 43 includes a video signal VD and an antenna output signal S based on the antenna output signal SA sequentially extracted by the video signal sampling unit 42.
B, the level of the video signal VD based on the antenna output signal SC, and the level of the video signal VD based on the antenna output signal SD are detected, and the level of the video signal VD based on the detected antenna output signal SA is detected. Level, the level of the video signal VD based on the antenna output signal SB, the level of the video signal VD based on the antenna output signal SC, and the video signal VD based on the antenna output signal SD.
Is supplied to the signal selection unit 44.

The signal selection unit 44 includes a level detection output signal DVL from the video signal level detection unit 43 which sequentially represents a level of the video signal VD based on the antenna output signal SA, a level of the video signal VD based on the antenna output signal SB, The level of the video signal VD based on the antenna output signal SC and the video signal V based on the antenna output signal SD
Each of the D levels is stored in a built-in memory, and they are compared with each other, and the largest one of them is the level DL1 and the second largest is the level DL.
The second largest and the third largest are set as level DL3, and the smallest one is set as level DL4. And the level DL
1, the video signal VD based on the antenna output signal SA, the video signal VD based on the antenna output signal SB, the video signal VD based on the antenna output signal SC, and the antenna output signal SD. One of the video signals VD based on the maximum level video signal VD1
And the video signal VD based on the antenna output signal SA, the video signal VD based on the antenna output signal SB, the video signal VD based on the antenna output signal SC, and the antenna output signal SD set as the maximum level video signal VD1. The selected output signal SX corresponding to one of the video signals VD based on the selected video signal VD is supplied to the reception signal switching control unit 45.

The received signal switching control unit 45
The vertical synchronization signal SV and the horizontal synchronization signal SH from 1 are supplied, and at least follow a specific period which is a period corresponding to, for example, an equivalent pulse following the vertical synchronization signal SV in the vertical blanking period of the video signal VD. During the period, when the selected output signal SX from the signal selection unit 44 corresponds to the video signal VD based on the antenna output signal SA, the selected output signal SX is
B, the selected output signal SX corresponds to the video signal VD based on the antenna output signal SC, and the selected output signal SX corresponds to the video based on the antenna output signal SD. The control signal SZ, which is different depending on each of the cases corresponding to the signal VD, is supplied to the diode drive signal forming unit 47. In such a case, the diode drive signal forming section 47
Is a control signal SZ from the reception signal switching control unit 45 during a period other than a specific period in the vertical blanking period of the video signal VD, and a selection output signal SX is the antenna output signal SA
, The switching diodes 15A to 15D.
A drive signal C1 for turning on the switching diode 15A is supplied to the anode of the switching diode 15A so that only the switching diode 15A of the switching diodes 15D is turned on, and the switching diodes 15B to 15D are supplied with them. An operation is performed in which the drive signals C2 to C4 for turning on are not supplied, and the control signal SZ from the reception signal switching control unit 45 is set to the selected output signal S
When X is a signal corresponding to the video signal VD based on the antenna output signal SB, the switching diode is turned on to turn on only the switching diode 15B among the switching diodes 15A to 15D. A drive signal C2 for turning on the switching diode 15B is supplied to the anode of the switching diode 15B, and the switching diodes 15A, 15C and 1
5D includes drive signals C1 and C for causing them to be turned on.
3 and C4 are not supplied, and the control signal SZ from the reception signal switching control unit 45 corresponds to the case where the selected output signal SX corresponds to the video signal VD based on the antenna output signal SC. At this time, a drive signal C3 for turning on the switching diode 15C is supplied to the anode of the switching diode 15C so that only the switching diode 15C among the switching diodes 15A to 15D is turned on. 15A, 15B and 15D have drive signals C1, C2 and C which cause them to be in the ON state.
4 is not supplied, and furthermore, the control signal SZ from the reception signal switching control unit 45 corresponds to the case where the selected output signal SX corresponds to the video signal VD based on the antenna output signal SD. At this time, a drive signal C4 for turning on the switching diode 15D is supplied to the anode of the switching diode 15D so that only the switching diode 15D among the switching diodes 15A to 15D is turned on. 15A to 15C perform an operation of not supplying drive signals C1 to C3 for turning them on.

Accordingly, in the vertical blanking period of the video signal VD, for example, during a period following a specific period which is a period corresponding to an equivalent pulse following the vertical synchronizing signal SV, the signal selection unit 44 sets the maximum level image. The video signal VD set as the signal VD1 is a video signal VD based on the antenna output signal SA, a video signal VD based on the antenna output signal SB, a video signal VD based on the antenna output signal SC, and a video based on the antenna output signal SD. Only one of the switching diodes 15A to 15D is turned on according to which of the signals VD, whereby the antenna output signal SA, SB, SC or SD is supplied to the tuner 31. State is taken. Thus, in a period following a specific period in the vertical blanking period of the video signal VD, the video detection unit 33 outputs the video signal VD based on the antenna output signal SA, the video signal VD based on the antenna output signal SB, and the antenna output signal. Video signal VD based on SC
The signal set as the maximum level video signal VD1 among the video signals VD based on the antenna output signal SD is transmitted.

The video signal VD set as the maximum level video signal VD1 sent from the video detection unit 33 is supplied to the ghost component separation unit 58 in addition to the video amplification unit 34, the synchronization separation unit 41 and the video signal sampling unit 42. Supplied. The ghost component separation unit 58 sets the video signal VD1 set as the maximum level video signal VD1 from the video detection unit 33 under the timing setting by the vertical synchronization signal SV and the horizontal synchronization signal SH from the synchronization separation unit 41. The ghost signal component SG included in the ghost signal component SG is separated and extracted, and the separated ghost signal component SG is supplied to each of the ghost component level detection unit 59 and the ghost number detection unit 60.

The ghost component level detection section 59 detects the level of the ghost signal component SG from the ghost component separation section 58 and outputs a ghost level detection output signal DGL representing the level of the detected ghost signal component SG to a signal selection unit. 44. Further, the ghost component number detection unit 60 detects the number of ghosts based on the ghost signal component SG from the ghost component separation unit 58,
A ghost number detection output signal DGC representing the number of detected ghosts is supplied to the signal selection unit 44.

In such a case, the signal selection unit 44
Based on the ghost level detection output signal DGL from the ghost component level detection section 59 and the ghost number detection output signal DGC from the ghost component number detection section 60, it is set as the maximum level video signal VD1 transmitted from the video detection section 33. The ghost state in the video signal VD is evaluated, and the maximum level video signal VD
It is determined whether or not the quality of the video signal VD set as 1 is equal to or higher than a preset reference. If the quality of the video signal VD set as the maximum level video signal VD1 is equal to or higher than a preset reference as a result of the determination, the video signal VD set as the maximum level video signal VD1 is converted to the highest quality video signal. The video signal VD is regarded as the video signal VD, and the selected output corresponding to the video signal VD set as the maximum level video signal VD1 until a specific period in the next vertical blanking period of the video signal VD thereafter comes. The transmission of the signal SX to the reception signal switching control unit 45 is continued.

As a result, the state in which the video signal VD set as the maximum level video signal VD1 is transmitted from the video detector 33 is maintained, and an image based on the video signal VD obtained from the video detector 33 is reproduced at that time. Together
At this time, a sound based on the sound signal AU obtained from the sound detector 38 is reproduced.

On the other hand, the maximum level video signal VD1
If the quality of the video signal VD set as the maximum level video signal VD1 is not equal to or higher than the predetermined reference as a result of the determination as to whether or not the quality of the video signal VD set as Is the signal selection unit 44
Stores the quality of the video signal VD set as the maximum level video signal VD1 in a built-in memory, and has the video signal VD having the level DL2 set as described above, that is, the antenna output signal SA. Signal VD based on antenna signal VD based on antenna output signal SB
D, one of the video signal VD based on the antenna output signal SC and the video signal VD based on the antenna output signal SD is set as the second-level video signal VD2, and the antenna output signal set as the second-level video signal VD2 A selected output corresponding to one of the video signal VD based on the SA, the video signal VD based on the antenna output signal SB, the video signal VD based on the antenna output signal SC, and the video signal VD based on the antenna output signal SD. The signal SX is supplied to the reception signal switching controller 45.

The reception signal switching control unit 45 again outputs the signal in a vertical blanking period of the video signal VD, for example, in a period following a specific period which is a period corresponding to an equivalent pulse following the vertical synchronization signal SV. Selection unit 4
4 corresponds to the video signal VD based on the antenna output signal SA, the selected output signal SX corresponds to the video signal VD based on the antenna output signal SB.
If the selected output signal SX corresponds to the video signal VD based on the antenna output signal SC, and if the selected output signal SX corresponds to the video signal VD based on the antenna output signal SD. Is supplied to the diode drive signal forming unit 47. Thereby, the diode drive signal forming section 47 performs the same operation as described above.

Therefore, in a period following a specific period in the vertical blanking period of the video signal VD, the video signal VD set as the second-level video signal VD2 in the signal selection unit 44 is converted into a video based on the antenna output signal SA. Signal VD, video signal VD based on antenna output signal SB, video signal V based on antenna output signal SC
D and a video signal VD based on the antenna output signal SD
, Only one of the switching diodes 15A to 15D is turned on, whereby the antenna output signals SA, SB, SC
Alternatively, a state where SD is supplied to the tuner 31 is set. Accordingly, in a period following a specific period in the vertical blanking period of the video signal VD, the video detector 33 outputs the video signal V based on the antenna output signal SA.
D, a video signal VD based on the antenna output signal SB, a video signal VD based on the antenna output signal SC, and a video signal VD based on the antenna output signal SD, which are set as the second-level video signal VD2, are transmitted. become.

The video signal VD set as the second-level video signal VD2 transmitted from the video detection unit 33 is supplied to the video amplification unit 34, the synchronization separation unit 41, and the video signal sampling unit 42, as well as a ghost component separation unit 58. Supplied to The ghost component separation section 58 outputs the video signal V set as the second level video signal VD2 from the video detection section 33.
The ghost signal component SG included in D is separated and extracted, and the separated ghost signal component SG is supplied to each of the ghost component level detector 59 and the ghost number detector 60.

The ghost component level detection section 59 detects the level of the ghost signal component SG from the ghost component separation section 58 and outputs a ghost level detection output signal DGL representing the level of the detected ghost signal component SG to a signal selection unit. 44. Further, the ghost component number detection unit 60 detects the number of ghosts based on the ghost signal component SG from the ghost component separation unit 58,
A ghost number detection output signal DGC representing the number of detected ghosts is supplied to the signal selection unit 44.

Then, the signal selection unit 44, based on the ghost level detection output signal DGL from the ghost component level detection unit 59 and the ghost number detection output signal DGC from the ghost component number detection unit 60, detects
3 evaluates the ghost state in the video signal VD set as the second-level video signal VD2, and obtains the second-level video signal VD obtained based on the evaluation result.
The quality of the video signal VD set as 2 is compared with the quality of the video signal VD set as the maximum level video signal VD1 stored in the memory. As a result, when the quality of the video signal VD set as the second-level video signal VD2 is equal to or higher than the quality of the video signal VD set as the maximum-level video signal VD1, the video signal is set as the second-level video signal VD2. The video signal VD is regarded as the highest quality video signal VD, and is set as the second-level video signal VD2 until a specific period in the next vertical blanking period in the subsequent video signal VD comes. The transmission of the selected output signal SX corresponding to the video signal VD to the reception signal switching control unit 45 is continued. Thereby, the video signal VD set as the second-level video signal VD2 from the video detection unit 33
Is maintained, and at this time, the video detector 33
Is reproduced based on the video signal VD obtained from the audio signal A and the audio signal A obtained from the audio detector 38 at that time.
A voice based on U is played.

As a result of comparing the quality of the video signal VD set as the second-level video signal VD2 with the quality of the video signal VD set as the maximum-level video signal VD1 stored in the memory, the second-level video signal is obtained. If the quality of the video signal VD set as the signal VD2 is not higher than the quality of the video signal VD set as the maximum level video signal VD1,
Video signal V set as maximum level video signal VD1
D is regarded as the highest quality video signal VD, and the video set as the maximum level video signal VD1 again until a specific period in the next vertical blanking period of the subsequent video signal VD comes. The selected output signal SX corresponding to the signal VD is sent to the reception signal switching control unit 45. As a result, the state where the video signal VD set as the maximum level video signal VD1 is transmitted from the video detection unit 33 is maintained, and at this time, an image based on the video signal VD obtained from the video detection unit 33 is reproduced, and At this time, a sound based on the sound signal AU obtained from the sound detector 38 is reproduced.

By doing so, at least during the period after each vertical blanking period in the video signal VD obtained from the video detection unit 33, the antenna output signals SA, SB, The one selected from the SC and the SD and supplied to the tuner 31 is within a vertical blanking period of the video signal VD or a vertical blanking period of a predetermined cycle of an integral multiple of the vertical cycle of the video signal VD. Antenna output signals SA, S sequentially extracted by a signal sampling operation performed in a specific period of
A comparison result obtained by mutually comparing respective levels of the video signal VD sequentially obtained from the video detection unit 33 according to B, SC, and SD, and an image from the video detection unit 33 obtained from the ghost component separation unit 58 Based on the state of the ghost signal component SG included in the signal VD, it is determined that the highest quality video signal VD can be obtained. Therefore, a plurality of antenna output signals SA, SB, SC
And SD, the selected antenna output signal SA, SB, SC, or SD, not only when the video signal VD does not include the ghost signal component SG but also when the video signal VD includes the ghost signal component SG. The probability that the video signal VD based on is the best in quality is
It will be significantly higher.

The signal selection unit 44 in the example shown in FIG. 1 as described above is constituted, for example, by using a microcomputer, and a program executed when a signal selection operation is performed in such a microcomputer. Is represented by a flowchart shown in FIG.

In the flowchart shown in FIG. 2, after the start, in step 61, the level detection output signal DVL from the video signal level detection section 43 is fetched, and in step 62, the level detection output signal DVL is obtained.
VL sequentially represent the level of the video signal VD based on the antenna output signal SA, the level of the video signal VD based on the antenna output signal SB, the level of the video signal VD based on the antenna output signal SC, and the video based on the antenna output signal SD. Each of the levels of the signal VD is stored in a built-in memory, and they are compared with each other, and the largest one of them is the level DL1 and the second largest is the level DL2 and the third largest. Things DL
3. The smallest one is set as the level DL4.

Next, in step 63, step 6
2, the video signal VD based on the antenna output signal SA, the video signal VD based on the antenna output signal SB, and the antenna output signal S having the level DL1 set at 2.
C based video signal VD and antenna output signal SD
Is set as the maximum level video signal VD1, and the video signal VD based on the antenna output signal SA set as the maximum level video signal VD1.
D, a video signal VD based on the antenna output signal SB, a video signal VD based on the antenna output signal SC, and a selected output signal SX corresponding to the video signal VD based on the antenna output signal SD. The state where the video signal VD set as the maximum level video signal VD1 is transmitted from the video detection unit 33 is set in a state where the video signal VD is transmitted to the switching control unit 45.

Thereafter, in step 64, the ghost level detection output signal DGL from the ghost component level detection section 59 and the ghost number detection output signal DGC from the ghost number detection section 60 are fetched. Based on the DGL and the ghost number detection output signal DGC, the video detector 33
A ghost state in the video signal VD set as the maximum level video signal VD1 transmitted from the VGA is evaluated, and based on the evaluation result, the quality of the video signal VD set as the maximum level video signal VD1 is set to a predetermined reference. It is determined whether or not this is the case. As a result, if the quality of the video signal VD set as the maximum level video signal VD1 is equal to or higher than the preset reference, the process returns to step 61, and
If the quality of the video signal VD set as the maximum level video signal VD1 is not higher than the preset reference,
Proceed to step 66.

In step 66, the quality of the video signal VD set as the maximum level video signal VD1 is stored in a built-in memory, and the antenna output signal SA having the level DL2 set in step 62 is stored. One of a video signal VD based on the antenna output signal SB, a video signal VD based on the antenna output signal SC, and a video signal VD based on the antenna output signal SD is set as the second-level video signal VD2. I do. Then, the video signal V based on the antenna output signal SA set as the maximum level video signal VD1
D, a video signal VD based on the antenna output signal SB, a video signal VD based on the antenna output signal SC, and a selected output signal SX corresponding to one of the video signals VD based on the antenna output signal SD. , The antenna output signal S set as the second level video signal VD2
A selected output corresponding to one of the video signal VD based on A, the video signal VD based on the antenna output signal SB, the video signal VD based on the antenna output signal SC, and the video signal VD based on the antenna output signal SD. Signal S
The state where X is transmitted to the reception signal switching control unit 45 is set, and the video detection unit 33 transmits the video signal VD set as the second-level video signal VD2.

Thereafter, in step 67, the ghost level detection output signal DGL from the ghost component level detector 59 and the ghost number detection output signal DGC from the ghost number detector 60 are fetched again. Based on the output signal DGL and the ghost number detection output signal DGC, the ghost state in the video signal VD set as the second-level video signal VD2 sent from the video detection unit 33 is evaluated, and the ghost state is obtained based on the evaluation result. The quality of the video signal VD set as the second-level video signal VD2 is compared with the quality of the video signal VD set as the maximum-level video signal VD1 stored in the memory at step 66. As a result, when the quality of the video signal VD set as the second-level video signal VD2 is equal to or higher than the quality of the video signal VD set as the maximum-level video signal VD1, step 61
When the quality of the video signal VD set as the second level video signal VD2 is not higher than the quality of the video signal VD set as the maximum level video signal VD1, the process proceeds to step 69.

In step 69, the video signal VD based on the antenna output signal SA set as the second-level video signal VD2, the video signal VD based on the antenna output signal SB, and the video signal V based on the antenna output signal SC.
D and a video signal VD based on the antenna output signal SD
, The video signal VD based on the antenna output signal SA set again as the maximum level video signal VD1, the video signal VD based on the antenna output signal SB, and the antenna A state in which the selected output signal SX corresponding to one of the video signal VD based on the output signal SC and the video signal VD based on the antenna output signal SD is transmitted to the reception signal switching control unit 45, and There is no situation where the video signal VD set as the maximum level video signal VD1 is transmitted from the detection unit 33, and then, the process returns to step 61.

[0041]

As is apparent from the above description, in the diversity receiving apparatus according to the present invention, a plurality of antenna output signals respectively obtained from a plurality of receiving antennas are selectively sequentially extracted for a predetermined short period. In other periods except the specific period in which the signal sampling operation is performed,
As one of the plurality of antenna output signals to be selected and taken out, each of the reception output signals sequentially obtained from the reception signal processing unit according to the antenna output signal sequentially taken out by the signal sampling operation. The comparison result obtained by comparing the levels with each other and the received output signal
Of the ghost signal components contained in each of
Ghost state based on level and number of ghosts
Based on the evaluation result , the antenna output signal determined to form the reception output signal considered to be the highest quality is selected, and is selected based on each of the plurality of antenna output signals. Not only when the reception output signal does not include a ghost signal component but also when the reception output signal includes a ghost signal component, the reception output signal based on the selected antenna output signal is determined to be the best in quality. Probability will be significantly increased.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an example of a diversity receiving apparatus according to the present invention.

FIG. 2 is a diagram showing an example in which the signal selection unit in the example shown in FIG. 1 is configured using a microcomputer;
4 is a flowchart illustrating an example of a program executed when the microcomputer performs a signal selection operation.

[Explanation of symbols]

 11A antenna connection terminal 11B antenna connection terminal 11C antenna connection terminal 11D antenna connection terminal 12A reception antenna 12B reception antenna 12C reception antenna 12D reception antenna 15A switching diode 15B switching diode 15C switching diode 15D switching diode 30 reception signal processing unit 31 Tuner 33 Video detection unit 41 Synchronization separation unit 42 Video signal sampling unit 43 Video signal level detection unit 44 Signal selection unit 45 Received signal switching control unit 46 Antenna output signal sampling control unit 47 Diode drive signal formation unit 58 Ghost component separation unit 59 Ghost Component level detector 60 Ghost number detector

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-1-188180 (JP, A) JP-A-58-79345 (JP, A) JP-A-2-296420 (JP, A) JP-A-3- 35624 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) H04B ⁷ /02-7/12 H04B 1/10-1/14

Claims (1)

(57) [Claims] A plurality of antenna connection terminals to which respective reception antennas are connected; and an antenna output signal selection unit for selecting and extracting one of a plurality of antenna output signals obtained through the plurality of antenna connection terminals. An antenna output signal selected by the antenna output signal selection unit is supplied, and a reception signal processing unit that forms a reception output signal based on the antenna output signal; and a reception output signal from the reception signal processing unit. A ghost component separation unit for separating and extracting a ghost signal component, and a ghost signal extracted by the ghost component separation unit
A ghost component level detector for detecting the level of the component, and a ghost signal extracted by the ghost component separator.
Ghost detection that detects the number of ghosts based on
In the fraction detection unit, in a specific period, the antenna output signal selection unit,
An antenna output signal sampling control unit for performing control for performing a signal sampling operation for sequentially extracting each of the plurality of antenna output signals obtained through the plurality of antenna connection terminals for a predetermined short period; and the antenna output signal in the specific period. a level detecting section for detecting the level of each of the sequentially retrieved antenna output signal from <br/> the selection section, on the basis of the level detected by the level detecting section, the upper
The antennas sequentially extracted by the antenna output signal selection unit
Having at least the maximum level of the tenor output signal
One and the one with the second largest level, respectively.
Specified as a large-level signal and second-level signal, and
Ghost component level detector and ghost component number detector
Go for each of the detected maximum level signals
Based on the level of the ghost signal component and the number of ghosts.
The quality of the maximum level signal to be
If it is above the standard, or the above-mentioned preset standard
Although not described above, the ghost component level detection unit and the
The second-order level detected by the
The level and ghost of the ghost signal component for the bell signal
Of the second-level signal evaluated based on the number of strikes
If the quality is equal to or greater than the
Selected as the signal to be supplied to the processing unit, the maximum Les
The quality of the bell signal is not higher than the preset standard,
If the quality of the second level signal is not higher than
Signal to be supplied to the reception signal processing unit.
A signal selection unit for selecting as No., in a period other than said specific time period, the reception for performing the operation that you left the signal that is selected by the upper SL signal selecting unit to the antenna output signal selecting section <br/> up And a signal switching control unit.