JPH03185932A - Transmission sharing equipment - Google Patents

Abstract

PURPOSE:To apply the equipment to a system with lots of channels and a narrow channel interval by providing a power synthesizing circuit or the like, thereby employing a channel filter having not so much high Q and frequency temperature stability. CONSTITUTION:A signal inputted from input terminals IN1-IN(n-1) is filtered by channel filters F1-F(n-1) independently of signals inputted from other input terminals and synthesized by a power synthesizing circuit JU1. On the other hand, a signal inputted from input terminals IN2-INn is filtered by channel filters F2-Fn independently of signals inputted from other input terminals and synthesized by a power synthesizing circuit JU2. Then two outputs are synthesized into one output by a 3dB hybrid circuit H. In this case, since the band of each channel filter is assigned alternately at the interval of one channel, the Q and the frequency temperature stability are relaxed and the equipment is applied even to a system with lots of channels and a narrow channel interval.

Description

DETAILED DESCRIPTION OF THE INVENTION (Al Industrial Application Field) This invention relates to a transmission sharing device that combines a plurality of transmission signals and transmits them to a common output line or antenna.

(b) Background of the Invention In recent years, cellular systems have come to be widely used in mobile communication systems such as car telephones using the 800 MHz band. In such a cellular system, one wireless base station is provided with a number of wireless channels depending on the traffic of that cell (wireless zone).

For example, in mobile communication systems such as the above-mentioned car telephones, where the number of users has been rapidly increasing recently, one radio base station requires a large number of channels, for example, 32 to 64 channels.

When arranging such a large number of wireless channels in one base station, base station antenna sharing technology is important from an economic standpoint, and the development of a transmission sharing device that combines multiple input signals into one output signal is important. It is hanging down.

fcl Prior Art The configuration shown in FIG. 8 or 9 is generally used as a power combiner, not only when it is used as an antenna duplexer as in the example described above.

In FIG. 8, Hl, I2 and I3 are each so-called 3
dB hybrid circuit, R1, R2 and R3 are each dummy loads. INI to IN4 are input terminals, and OUT is an output terminal. The 3dB hybrid circuit H1 combines the power of the signals input from INI and IN2 and gives it to the 3dB hybrid circuit H3, while the 3dB hybrid circuit H2 combines the power of the signals input from IN3 and IN4 to provide the power of the signal input from the 3dB hybrid circuit H3. feed to the other input. The 3 dB hybrid circuit H3 combines the powers of both input signals and outputs the resultant signal.

In FIG. 9, Il, I2...In are isolators, Fl, F2...Fn are channel filters each consisting of a bandpass filter, and JU is each channel filter F1. F2...This is a power combining circuit (junction unit) consisting of branch lines that combine the outputs of Fn. ■Each signal input from Nl, IN2...INn is prevented from going around to other input terminals by isolators Il, 12...In, and the signal passes through channel filter Fl, F2...F rx. are combined in power by junction unit JU and output.

(d1 Problems to be Solved by the Invention The so-called 3dB hybrid power system shown in Figure 8 is a simple system with no frequency characteristics in principle, but every time it passes through the 3dB hybrid circuit, half of the power is transferred to a dummy load. Therefore, it is generally not used as a shared transmission device for transmitting power.

On the other hand, the so-called junction unit synthesis method shown in Fig. 9 uses a channel filter that passes a predetermined channel band and inputs the signals of the corresponding channels, making it possible to perform power synthesis with low shared loss. -e is used as a shared transmission device.

The relationship between each channel and the transmission characteristics of each channel filter is as shown in FIG. In the same figure,
, f2. f3... is the center frequency of each channel and each channel filter. In this way, in order to reduce interference with adjacent channels, a Q higher than a predetermined value is required, and in order to suppress the increase in insertion loss due to center frequency displacement due to temperature, high frequency temperature stability is required. sexuality is required. But for example 800
Channel spacing is 10 in the MHz to 1.5GHz band
When applied to a system where the frequency is 0kHz, it is difficult to construct a channel filter with stable frequency-temperature characteristics while maintaining a high Q even in a cavity resonator, semi-coaxial cavity resonator, dielectric resonator, etc. This was difficult and resulted in a large insertion loss.

An object of the present invention is to provide a transmission sharing device that uses a channel filter that does not have a very high Q and frequency temperature stability, and that can be applied to a system with a large number of channels and narrow channel spacing.

(81 Means for Solving Problems) The transmission sharing device of the present invention includes a plurality of channel filters that pass the band of each transmission channel, an isolator connected to the input of each of these channel filters, and an isolator connected to the input of each of the channel filters. A plurality of sets of power combining circuits consisting of branch lines that combine the outputs as one output are provided, and a hybrid circuit is provided for each of the two sets of power combining circuits to combine the outputs, and the band of each channel filter of the same power combining circuit is A feature is that the bands of each channel filter are selected in such a manner that the bands are the most distant from each other.

(f) Effect An example of the configuration of this invention is shown in FIG.

In Fig. 1, Fl, F3...Fn-1, l'2,
F4...Fn are channel filters that pass the band of each assigned transmission channel, and isolators 11. I3・
...In-1, 12, 14...1. n is connected. In addition, channel filters Fl, F3...Fn
-1 output is connected to a power combining circuit (junction unit) consisting of a branch line that uses each of these outputs as one output.Channel filter F2
．． A power combining circuit (junction unit) JU2 consisting of other branch lines is connected to the outputs of F4...Fn. These two power combining circuits JUL and JU
A 3dB hybrid circuit H1 is connected to the output of No.2.

In the example shown above, the input terminals INI, IN3...l
The signal input from Nn-1 is input to input terminal IN2. IN
4...INn is filtered independently by channel filters Fl, F3...Fn-1, and is output as one output by the power combining circuit Jul. On the other hand, input terminals IN2, 1N4...
The signal input from INn is input to input terminals INI, IN3.
. . channel filter F2 . . . independently of the signal input from lNn-1. It is filtered by F4...Fn and output as one output by the power combining circuit JU2. These two outputs are further converted into a single output by a 3 dB hybrid circuit H.

Figure 2 shows each channel filter F1 to F shown in Figure 1.
It shows the transmission characteristics of Fl-F6 among n. Here f
1 to f6 correspond to the resonant frequencies of the channel filters F1 to F6, and the transmission characteristics of the channel filter connected to the power combining circuit JUL are shown in the upper row, and the transmission characteristics of the channel filter connected to the power combining circuit JU2 are shown in the upper row. The transmission characteristics of are divided into the lower rows. In this way, the bands of each channel filter connected to one power combining circuit are alternately assigned to every other channel. Therefore, the channel spacing of each signal input to one power combining circuit is doubled, and interference with adjacent channels is reduced. Therefore, the Q and frequency temperature stability required for each channel filter are relaxed. Conversely, even when using channel filters with the same Q and frequency temperature stability, it is possible to apply the system to a system having a larger number of channels with narrower channel spacing.

Note that due to the action of the hybrid circuit H and the dadan load R shown in FIG. Compared to the case where only a simple junction unit synthesis method is used as shown in the figure, the insertion loss in each channel filter is reduced, so it is possible to achieve a low insertion loss as a whole.

(Phantom Embodiment The structure and circuit diagram of a transmission sharing device which is an embodiment of the present invention is shown in FIGS. 3 to 5.

FIG. 3 is a schematic plan view showing the structure of the main parts of the shared transmission device, and FIG. 4 is a schematic cross-sectional view of the entire device taken along line AA in FIG. 3. In FIG. 3, F1 to F32 are TMs that pass the respective assigned channel bands.
□. This is a channel filter consisting of a mode dielectric resonator. The outputs of the odd-numbered channel filters F1 to F31 are output as one output by a power combining circuit (hereinafter referred to as a junction unit) JUI consisting of branch lines. On the other hand, each output of the even-numbered channel filters indicated by F2 to F32 is outputted as one output by the junction unit JU2. C1,
C2 is a circulator, and each dummy load R
1 and R2 are connected. Circulator C1 outputs the output of junction unit JUI to connector OUT
The circulator C2 guides the output of the junction unit JU2 to the output connector OUT.

Junction Units) In JUI, the electrical length up to the first branching point a, the channel filter F5. F7. F
The electrical length from each output of F13 and F15 to the first branch point C, the channel filter FLY, F19. Electrical length from each output of F25 and F27 0 to the first branch point e, channel filter F
21. F23. The electrical length from each output of F29 and F31 to the first branch point g is set to an odd multiple of 174 wavelengths. Similarly, junction unit J
In U2, channel filter F2. F4. F.I.O.
and the electrical length from each output of F12 to the first branch point, channel filter F6. FB, F14 and F16
The electrical length from each output to the first branch point d, the channel filter F18. F20. Electrical length from each output of F26 and F28 to the first branch point f, channel filter F22. F24. The electrical length from each output of F30 and F32 to the first branch point 11 is set to be an integer multiple of a quarter wavelength, which is an odd number. Similarly, the electrical length from the branch points s, d, f, and h to the second branch point j is set to be an integral multiple of 1/2 wavelength. By configuring the junction unit in this way, the impedance seen from each branch point to the other channel filter becomes extremely large at the frequency of the design wavelength, and the transmission power of the own channel can be transferred to the circulator C1° with almost no loss. Power is supplied to C2. Similarly, the coupling attenuation factor with other transmitters (circuits that supply transmission power to channel filters via isolakes) also increases, reducing interference between transmitters.

FIG. 4 shows the internal structure of channel filter F4. Here, 100 is a ceramic cavity, and 101 is a columnar internal dielectric body integrally formed between the bottom surface and the top surface of the cavity.
A mode dielectric resonator is configured. 102 and 103 are a signal input coupling loop and a signal output coupling loop for this resonator. Thirty-two channel filters having such a configuration are arranged and housed between metal plates (cases). In the same figure, IN2. IN4. IN6 and IN8 are input connectors, respectively, and I2I4 16 and I8 are isolators that feed the 2 signals from each input connector to the coupling loop of each resonator (channel filter). Moreover, J Ub is the channel filter F2. shown in FIG. This is a branch line that couples the outputs of F4, FIO, and F12 (outputs of the above-mentioned coupling loop) to point b with an electrical length that is an odd multiple of 1/4 wavelength. J
Ud is the channel filter F6. shown in FIG. F8.
Each output of F14 and F16 is an integer multiple of 1/4 wavelength.
It is a branch line that connects to a point. These branch lines in the second stage are formed by patterns on a board as, for example, strip lines or transmission lines, and the branch lines in the second stage are formed by coaxial cables or the like.

FIG. 5 is a circuit diagram of the entire transmission sharing device. Here, the channel assigned to channel filters F1 to F32 is equal to the number of that filter. That is, the junction unit JUI combines the outputs of the channel filters F1 to F31 that pass odd-numbered channels, and the junction unit JTJ2 combines the outputs of the channel filters F2 to F32 that pass even-numbered channels. The output of the junction unit JUI passes through the circulator C1, and 1/2 of the power is output from the output terminal OUT, and 1/2 of the power passes through the circulator C2 and is consumed by the load R2. Further, the output of the junction unit JU2 passes through the circulator C2, and 1/2 of the power is output from the output terminal OUT, and 1/2 of the power passes through the circulator C1 and is consumed by the load R1.

The embodiment shown above is a 32-channel transmission sharing device, but when configuring an even more multi-channel transmission sharing device, multiple sets of transmission sharing devices with the above circuit configurations are provided, and their outputs are hybridized. Power can be combined using a circuit.

FIG. 6 is a circuit diagram of an example. In Figure 6, F
1 to F64 are channel filters, which pass the band of the channel equal to the filter number. IN
I to IN64 are input terminals, each of which provides an input signal to each channel filter through an isolator. JUL is a junction unit that uses the outputs of channel filters Fl, F5...F61 as one output, and JU2 is a junction unit that uses channel filters F3... F7...junction unit that bases the output of F1a, JU3 is the channel filter F
2. Junction unit 7 connects the output of F6...F62, and JU4 is a channel filter F4... F
8...This is a junction unit that connects the output of F64. Hl, R2 and R3 are R1, R2 respectively
This is a 3dB hybrid circuit with R3 and R3 as dummy loads. The 3dB hybrid circuit H1 bottoms out the outputs of the two junction units Jul and JU2,
The 3dB hybrid circuit H2 outputs the outputs of the other two junction units JU3 and JU4. Furthermore, the 3 dB hybrid circuit H3 bottoms out the outputs of the hybrid circuits H1 and R2.

FIG. 7 is a diagram showing channels assigned to each channel filter shown in FIG. 6 and transmission characteristics. In the figure, (1) to (4) are the transmission characteristics of each channel filter that supplies signals to the junction units JUI to JU4 shown in FIG. 6, respectively. By setting the bands of the channel filters connected to each junction unit to be the most distant from each other in this manner, the influence of interference between the channel filters and between the transmitters connected thereto is minimized.

(h1 Effect of the invention According to this invention, the passband of the channel filter connected to one power combining circuit consisting of branch lines is wider than the overall channel spacing to be transmitted, so In addition, even when using channel filters with the same Q and frequency temperature stability, a large number of narrow channel spacings can be combined without increasing insertion loss. Channels can now be sent.

6

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing an example of the configuration of a shared transmission device of the present invention, and FIG. 2 is a diagram showing channels and transmission characteristics of a channel filter used in the device. Figures 3 and 4
The figures are a schematic plan view and a schematic cross-sectional view showing the structure of a shared transmission device according to an embodiment of the present invention. FIG. 5 is a circuit diagram of the same device. FIGS. 6 and 7 are circuit diagrams of a transmission sharing device according to other embodiments, and diagrams showing the channels and transmission characteristics of each channel filter. FIG. 8 and FIG. 9 are diagrams each showing a conventional power system. Furthermore, FIG. 1O is a diagram showing channels assigned to the channel filter shown in FIG. 9 and their transmission characteristics.゛■-Isolator, F-channel filter, JU-power combining circuit (junction unit), H-hybrid circuit. 5th UT

Claims (1)

[Claims] (1) A power source consisting of multiple channel filters that pass the band of each transmission channel, an isolator connected to the input of each of these channel filters, and a branch line that combines the outputs of the above channel filters as one output. A plurality of sets of combining circuits are provided, and a hybrid circuit for combining the outputs of each of the two sets of power combining circuits is provided, and the bands of the channel filters of the same power combining circuit are set in such a manner that the bands of the channel filters of the same power combining circuit are farthest from each other. A transmission sharing device characterized by the following: