JPS5880976A - Microwave transmitter - Google Patents

Abstract

PURPOSE:To obtain a small-sized, economical, and low-priced microwave transmitter for multiple CHAM transmission of television broadcast waves, by adopting a single conversion type VH discriminator. CONSTITUTION:A television broadcast wave is branched through a branching filter 2 to the two VHF band-pass filters 11a and 11b, and a UHF band-pass filter 10. After a UHF television broadcast wave is converted into a signal of a VHF mid-band DCH, forms the 1st VHF television signal group together with the 1st and 3rd CH signals of the VHF television broadcast wave. Respective signals have nonlinear distortion improved and are converted into the 1st and 2nd microwave television signal groups, then a polarization discriminator 20 radiates the 1st and 2nd microwave television signal groups from an antenna 7 as a horizontal polarized wave H and vertical polarized wave V.

Description

[Detailed description of the invention] The present invention relates to a microwave transmission device for transmission.

In urban areas, there are many areas where television broadcast waves are difficult to receive due to the construction of high-rise buildings, which has become a problem.

Conventionally, a microwave transmitter for multi-CHAM transmission has been used as a means of solving such difficult-to-see areas, and the methods include an individual amplification method and a common amplification method. However, the former is economically expensive and large in size, and the latter requires a double conversion system and has constraints such as the need to have a sufficiently large amount of pack-off for the amplifier, making it expensive. 0 FIG. 1 and FIG. 2 show examples of such a conventional 7 CH individual amplification method and a 7 CH common amplification method, respectively.

In Figure 1, the individual amplification methods are each a UV frequency converter! , 08 frequency converter 4, S-band amplifier 5, and 8 band pass filter 6 are prepared for 7 channels), and four antennas 7 are used. Further, in FIG. 2, the common amplification method requires a double conversion method, and the number of frequency converters is also increased.

SUMMARY OF THE INVENTION An object of the present invention is to provide a microwave CH television transmitting apparatus that eliminates the above-mentioned drawbacks and can be made economically inexpensive and compact by adopting a single convergence system and a vH discriminator.

In order to achieve the above object, the microwave sending and receiving device according to the present invention includes means for converting the frequency of X UHF television broadcast waves and FM independent broadcast waves into a 110-144 MHz band, and an output of the frequency converting means and a frequency converter of 90-108 MHz.
8B means for creating a first VHF television signal group including VHFfv vision broadcast waves, and 170 to 222
MHz @V8BVHF The second V of television broadcast waves
means for creating a group of HF television signals;
a VHF band pre-nonlinear distortion compensator that respectively compensates third-order nonlinear distortion of the second VHF television signal group;
means for frequency converting the first and second VHF television signal groups output from the HF band pre-nonlinear distortion compensator into first and second microwave television signal groups, respectively;
one or two local oscillators for frequency conversion into a second microwave television signal group; a bandpass filter for removing unnecessary waves from the first and second microwave television signal groups; a polarization discriminator that makes one of the first and second microwave television signal groups output from the band filter filter vertically polarized and the other horizontally polarized; and an antenna that radiates the vertically and horizontally polarized waves. It consists of

According to the above structure, the object of the present invention is completely achieved.

Hereinafter, the present invention will be explained in more detail with reference to the drawings.

FIG. 3 is a diagram showing the frequency arrangement of television broadcast waves in Japan. In Japan, the television broadcast wave channels 1, 3, 4, 6, 8, 1112 and their video carrier waves are as shown in Figure 3. Mae, U! (F
Also shown is a DCH that is assumed to have been frequency-converted from a television broadcast wave to a vHF mid-band DCH, that is, a video carrier wave of 129.25 MHz.

In the present invention, CHI, 3, and D are the first VHF television signal group, and CH%41618, 10, and 12 are the second VHF television signal group.
This is the F television eye signal group.

FIG. 4 is a circuit block diagram showing an embodiment of the microwave transmitter according to the present invention.

In the figure, the television broadcast waves are transmitted through the distributor DI and the VHF bandpass filter 11a111b and the UHF bandpass filter 11a111b.
The signal is distributed to a bandpass filter 10 .

As a result, the video carrier wave of VHF television broadcast wave 1.30H is transmitted from the filter 11m, and the UH video carrier wave is transmitted from the filter 10.
The video carrier wave of the F television broadcast wave is transmitted from the filter 11b to the VHF television broadcast wave No. 4.6.8.10.1.
A 2CH video carrier wave is output. [JI (F television broadcast wave line UV frequency converter 13 converts vHF mid-band DCH, S-hb video carrier wave 129.2
After being converted to 5MHz, a first VHF television signal group is formed together with the vHF television broadcast wave 1.3CH by a VHF band hybridizer, and vlH'
The signal is input to the band amplifier 14a.

On the other hand, the VHF television broadcast wave No. 4.6.8.10.12 CH output from the filter 11b is the second VHF
It is input to the VHF band amplifier 14b as a television information group.

In the VHF band predistortion compensator 15 a % 15 b, the first
and the second Vl(F), the third-order nonlinear distortion of the television signal group is improved, and the upper sideband frequency converter 1
At 6a%16b, the 1.44th s'oVHF television signal group is converted into the 11th microwave television signal group.

In FIG. 5, the frequency of local oscillators 17m and 17b is fL.

This figure shows the output frequencies and arrangement of the frequency converters 16m and 16b when

In FIG. 5, the frequency converter 16m outputs the microwave television signal group 10i in the frequency band (1), and the frequency converter 16b outputs the second mitowave television signal group in the frequency band (2). Output.

FIG. 6 shows the characteristics of the frequency converter 16m when the local oscillator power is +25 dBm.

In Fig. 6, one point is usually called the intercept point, and the output power +10 dBm and 1k (J-order OI
MoD/lJ = 20dB, D/U- of 3rd order OIM
40dB, local leak D/U = -8dB.

If the characteristics of the polarized bandpass filter 68 in FIG. 4 are shown in FIG.
MD/U4 addition +24 = 44dB.

3rd order IM D/U = 40dBJ' local leakage D
/U Gourd-8+61-Guo (iB stop.

Now, the spurious emission D/[7-
Considering the regulation of 40 dB or more, it can be said that these are satisfied, but as shown by the dotted line in Figure 5 and 9, the secondary IM
and the third-order IM fall into each transmission band, respectively D
/U=44dB and D/U-+oan. Therefore, when transmitting TV broadcast waves over 3 channels, D/
U is usually required to be 70 dB or more, so each 30 dB
You'll end up with no legs.

However, regarding the third-order IM, the predistortion compensator 15a shown in FIG. 4 can improve 30 dB, and 1D/U=4
0+30=70dB. However, with regard to the secondary IME, we cannot expect much because the frequencies are too far apart.

Moreover, it is not a good idea to seek an additional 30 dB improvement with the bandpass filter 19a in FIG.
It is extremely difficult to do so at frequencies above Hz.

Therefore, in the present invention, the first microwave television signal group is horizontally polarized by the polarization discriminator shown in FIG. 4, and the second microwave television signal group is vertically polarized and radiated from the antenna 7. ing.

With this, the discrimination degree of 9V/H can be obtained as 30 dB, so in the end, the secondary OIM (2) D/U-44 + 30 = 74 dB Tona〉, secondary, 8K (DIM and 4 D/Uij70 dE
The above can be satisfied.

FIG. 8 is a characteristic diagram of the bandpass filter 19b.

This second television signal group also has the same characteristics as the first signal group, and can obtain the same characteristics as described above.

FIG. 9 is a circuit plotter diagram showing a second embodiment of the present invention. This diagram shows the local oscillator 17 output as the hybrid 21
Although this embodiment differs from the embodiment shown in FIG. 4 in important points in that it is configured to be distributed to frequency converters 16& and 16b, the configuration of other parts remains the same. Note that the first and second embodiments also showed examples in which the first microwave television signal e was horizontally polarized and the second microwave television signal group was vertically polarized; There is no problem in making it compatible. In addition, 1, 3, DC) It was set as the first OVHF television signal group, and as shown in Fig.
, AlFCH as a first VHF television signal group;
Television or FM independent broadcast waves to ACH, UHF
It is also possible to frequency convert television broadcast waves and input them into FCH.

As described in detail above, according to the present invention, it is possible to provide an economically inexpensive and compact microwave CH television transmitting device that does not require a double conversion method. In addition to all the television broadcast waves that are currently broadcast in Japan and can be viewed at home, there is also an additional 2 channels of independent broadcast waves, totaling 10C.
It is possible to transmit up to 1 (.

For example, if you put this in the Tokyo area, 1 television broadcast wave 1.3 Cf (and television or FM independent broadcast wave 1 to 2 C) l, UHF frequency converted to VHF.
Television broadcast wave I CH total 4 to 5 CH and television broadcast wave 4% 618.10.12 C) 5c of I
)(can be transmitted simultaneously with one antenna.

[Brief explanation of the drawing]

Figure 1.2 is a circuit block diagram showing a configuration example of a conventional microwave television multi-channel transmitter, Figure 3 is a frequency allocation diagram of television broadcast waves in Japan, and Figure 4 is a transmitter according to the present invention. FIG. 5 is a circuit block diagram showing an example of the frequency arrangement of the microwave band television signal of the present invention. FIG. 6 is an operating characteristic diagram of the frequency converter of the present invention. 9 is a characteristic diagram of the microwave bandpass filter of the present invention, FIG. 9 is a circuit block diagram showing another embodiment of the present invention, and FIG. 1O is a frequency arrangement of the microwave band television signal of the present invention. It is a figure which shows another example. 1-VHF UHF television signal input terminal 2...Distributor 3a-3g-VU frequency converter 4.41-4g/-U8 frequency converter 5.51-5g-8 Electrical amplifier 61-6g-8 band Pass filter 7.71~7g...Antenna 8...Synthesizer 9-/S-band prefix non-direction distortion compensator 11a% llb ・-VHF1111 pass filter 1
G-UHF band bandpass filter 13-UV frequency converter 12-VHF band hybrid 14a s 14 b,,vnp electric amplifier 15m,
15b-VHF band predistortion compensator 17.17as 17b
...i Italo wave local oscillator 16m, 16b--Mitalo wave frequency converter 18a, 18b...Circulator 19m, 19b--Microwave band-pass filter 20-
...Polarization discriminator U- ...miter wave hybrid (distributor) patent applicant NEC Gold Wire

Claims (1)

[Claims] 11 UHF television broadcast waves or FM independent broadcast waves
0 to 144 MH, a means for converting the frequency into a band, and an output of the frequency converting means and 90 to 108 MHsllV3BVHF.
means for creating a 10th VHP television broadcast signal group including television broadcast waves, and 170-222 MHz wV
8B means for creating a second VHF television signal group of VHFy registration broadcast waves;
a VHP band pre-nonlinear distortion compensator for compensating the third-order nonlinear distortion of the F television broadcast signal group; and the VHF IIF.
means for frequency converting the first and second VHF television signal groups output from the pre-nonlinear distortion compensator into first and 20th Ita Tanami television signal groups, respectively; and the first and second microwaves. one or two local oscillators for frequency conversion into a television digital signal group; a bandpass filter for removing unnecessary waves from the first and second microwave television signal groups; and the bandpass filter. A micrometer comprising a polarization discriminator that makes one of the first and second output microwave television signal groups vertically polarized and the other horizontally polarized, and an antenna that radiates the vertical and horizontal polarized waves. wave transmitting device,