JPH026642Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a band-stop wave device used in an analog/digital combined microwave communication system that performs analog communication and digital communication through the same propagation route.

Conventional technology Band-stop equipment used in analog/digital microwave communication systems that perform analog communication and digital communication over the same propagation route in microwave communication is the center of analog communication from the standpoint of effective frequency utilization. With frequency ₀ a,
If the frequency difference from the center frequency of digital communication ₍₀ d) is reduced to 100 MHz for the same polarization or 60 MHz for different polarization, interference between transmitted and received signals from the digital communication side to the analog communication side will occur. becomes a problem.

Therefore, in order to prevent this interference, a microwave band-stop filter is installed, and its center frequency ₀ r is set slightly closer to the center frequency ₀ d for digital communication than the center frequency ₀ a for analog communication. 30dB over the center frequency _0r ±20MHz
Attenuation above and above center frequency
It is necessary to pass ₀ d±20MHz with almost no loss.

When such a microwave band-elimination waveguide is constructed with a five-stage Tiebishiev-type waveguide, the first
It will look like 1' shown in the figure. FIG. 2 schematically shows the attenuation characteristics of this wave device, and FIG. 3 schematically shows the delay time characteristics. As can be seen from Figure 3, the center frequency of digital communication _{is 0} d±20M.
The delay time deviation at Hz is as much as 7.3 ns, but on the repeater side, in addition to equalizing the delay time characteristics of the splitter used separately, it is also necessary to equalize the delay time characteristics of such a band-stop filter. Because it is difficult to do
It has been difficult to make effective use of frequencies in conventional analog and digital microwave communication systems.

Purpose of the invention The purpose of the invention is to provide an easy-to-use band-stop waveform for analog/digital microwave communication systems in which the delay time characteristics of the digital signal passband are well equalized and the insertion loss characteristics are also flattened. The goal is to provide equipment.

Composition of the invention In order to achieve the above-mentioned purpose, the band-stop wave device of the invention for a microwave communication system that combines analog and digital has an attenuation characteristic for the analog signal band and a pass characteristic for the digital signal band. a microwave band-elimination waveform device having a delay time characteristic opposite to that of the digital signal band of the microwave band-elimination waveform device; It is characterized by comprising a delay time equalizer.

Embodiment Hereinafter, an embodiment of a band-stop wave device for an analog/digital combined microwave communication system according to the present invention will be described in detail with reference to the drawings. In Fig. 4, reference numeral 1 indicates a waveguide 1a with a plurality of cavity resonators 1b fixed at predetermined intervals to have an attenuation characteristic for the analog signal band and a pass characteristic for the digital signal band. This is a tube-shaped microwave band-stop wave device, and in this embodiment, a Tiebishiev-type five-stage configuration was used. Reference numeral 2 denotes a so-called twin H-bend connected to one end of this microwave band-elimination device 1. This twin H-bend has a structure in which the first H-bend 2A and the second H-bend 2B are integrated with the output end of the former and the input end of the latter adjacent to each other, and the input end of the former is connected to the microwave. is connected to the output terminal _A2 of the band-stop filter 1. 3 is a well-known short slot type 3 dB coupler connected to the twin H-bend 2; the input terminal of this coupler is connected to the output end of the first H-bend 2A, and the directional terminal is connected to the input of the second H-bend 2B. They are connected at each end. 4 is a total reflection type wave waver unit connected to the 3 dB coupler 3, and this waver unit includes two total reflection type band wave wavers 4A and 4B each having a two-stage configuration.
The input and output terminals of the first wave generator 4A are connected to the passing terminals of the 3 dB coupler 3,
The input and output terminals of the second wave generator 4B are connected to the coupling terminal of the 3 dB coupler 3. 4a and 4b are screws for adjusting the center frequency of wave generators 4A and 4B, respectively. The above total reflection type band wave transducer 4A, 4B, 3dB
The coupler 3 and the twin H-bend 2 constitute a delay time equalizer 5 that equalizes the delay time characteristics of the microwave band-elimination filter 1. The delay time equalizer 5 is provided with a delay time characteristic opposite to that of the digital signal band of the microwave band-elimination filter. The microwave band-elimination device 1 and the delay time equalizer 5 constitute a band-elimination device for an analog/digital combined microwave communication system according to the present invention. Input end A ₁ becomes the microwave input end, and H bend 2B output end
A ₃ is the output end of the microwave.

FIG. 5 shows an electrical equivalent circuit of the above-mentioned band-stop wave device for analog/digital combined microwave communication system. Equivalent circuits 13 correspond to the twin H-bend 2, 13 corresponds to the 3 dB coupler 3, and 14 corresponds to the total reflection type band wave generators 4A and 4B, respectively. Ql ₁ to _{Ql 3} in Figure 5
and Q′l ₁ , Q′l ₂ , etc. are the Q of each resonant circuit when loaded, and λg is the tube wavelength of the radio wave at the center frequency.

Next, the center frequency is
₀ r=11200MHz, Ql ₁ = 265.9, Ql ₂ = 139.7, Ql ₃ =
121.4, and the waveguide diameter is 22.9 × 10.2 mm ² , and for the total reflection type band wave transducers 4A and 4B, the center frequency ₀ is ₀ = ₀ d + 28.5 MHz, and Q′l ₁ / ₀ = 6.5 G.
Hz ^-1 and Q′l ₂ / ₀ = 21.45 GHz ^-1 , and when the waveguide diameter is the same as above, the passband of the band-stop wave device for an analog/digital microwave communication system according to the present invention is The delay time characteristics at ₀ d±20MHz were as shown in Figure 6. The curve in the same figure shows the delay time characteristic of the passband of the band-stop filter 1, the curve shows the delay time characteristic of the delay time equalizer 5, and the curve shows the delay time characteristic after equalization by the equalizer 5 (i.e., the sum of the curves). It is something that In addition, the passband of the band-stop wave device for the analog/digital microwave communication system is ₀ d±20MHz.
The insertion loss characteristics were as shown in FIG. The curve in the figure shows the insertion loss characteristic of the band-elimination filter 1, the curve shows the insertion loss characteristic of the delay time equalizer 5, and the curve shows the insertion loss characteristic after equalization (that is, the sum of the curves). That is, in the band-stop wave device for an analog/digital combined microwave communication system according to the present invention, the delay time characteristics of the digital signal passband are well equalized as shown in the curve of FIG. As seen in the curve of FIG. 7, the insertion loss characteristics of the digital signal passband are flattened.

In the above embodiment, the microwave band-elimination filter 1 has been described as having a five-stage Tievisiev-type configuration, but other shapes and numbers of stages may be used.

Furthermore, in the above embodiment, the total reflection waveform used to equalize the delay time of the digital signal band has a two-stage structure, but the number of stages is not limited to this.

Furthermore, the delay time equalizer in the present invention may be a combination of a total reflection waveform and a circulator.

Effects of the invention As described above, the band-stop wave device for an analog/digital combined microwave communication system according to the invention is capable of handling microwave signals that have attenuation characteristics for the analog signal band and pass characteristics for the digital signal band. A delay time equalizer having delay time characteristics opposite to the delay time characteristics of the digital signal band of the microwave band-elimination device is connected to one end of the microwave band-elimination device. In microwave band-stop wave filters, when the frequency interval between the analog signal attenuation range and the digital signal passband is narrow, the delay time characteristic in the digital signal passband rises too much, which is difficult to use. According to the present invention, an easy-to-use band-stop wave device for an analog/digital combined microwave communication system is provided in which the delay time characteristics of the digital signal passband are well equalized and the insertion loss characteristics are also flattened. can do. Therefore, the present invention is suitable for an analog/digital microwave communication system that performs analog communication and digital communication using the same propagation route by minimizing the difference in the center frequency of each communication method as much as possible. Band-stop wave devices for analog and digital microwave communication systems can be used extremely effectively, and have the advantage of being easy to use frequencies effectively.

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing an example of a conventional microwave band-stop waver, Fig. 2 is a characteristic curve diagram schematically showing the attenuation characteristics of the band-stop waver shown in Fig. A characteristic curve diagram schematically showing delay time characteristics,
FIG. 4 is a perspective view showing an embodiment of a band-stop wave device for an analog/digital combined microwave communication system according to the present invention, FIG. 5 is a circuit diagram showing an electrical equivalent circuit of this embodiment, and FIG. 7 is a characteristic curve diagram showing the delay time characteristics of this embodiment, and FIG. 7 is a characteristic curve diagram showing the insertion loss characteristics of this embodiment. 1...Microwave band stop waver, 2...Twin H bend, 2A...First H bend, 2B...
...Second H-bend, 3...3dB coupler, 4A, 4
B... Total reflection type band wave generator, 5... Delay time equalizer.

Claims (1)

[Scope of utility model registration request] A band-stop wave device used in an analog/digital combined microwave communication system that performs analog communication and digital communication using the same propagation route has an attenuation characteristic for the analog signal band and an attenuation characteristic for the digital signal band. a microwave band-elimination waveform having a pass characteristic; and a microwave band-elimination waveform having a delay time characteristic opposite to the delay time characteristic of the digital signal band of the microwave band-elimination waveform at one end of the microwave band-elimination waveform. A band-stop wave device for an analog/digital combined microwave communication system consisting of a connected delay time equalizer.