JPS6110328A - Receiver for satellite communication - Google Patents

Abstract

PURPOSE:To simplify the constitution of a high frequency signal reception section by transmitting a local oscillation signal to a high frequency signal processing section and transmitting an intermediate frequency signal from the high frequency signal reception section to an intermediate frequency signal processing section. CONSTITUTION:A receiver consists of a high frequency signal reception section 10, an intermediate frequency signal processing section 20 and a coaxial cable 30 connecting them. The intermediate frequency amplifier circuit 17 transmits an intermediate frequency signal to the cable 30 via a demultiplexing and synthesis circuit 21 taking the attenuation of the cable 30 into account. The intermediate frequency signal processing section 20 has an oscillator 23 constituting a local oscillation circuit and a local oscillation signal LOS is given to a local oscillation signal amplifier circuit 15 via the cable 30.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a receiving device for satellite communication, and is particularly intended to stably process received signals with a simple configuration.

[Background technology and its problems]

In general, a receiving device that receives signals transmitted by an artificial satellite is equipped with a high-frequency signal receiving section integrated with an antenna placed outdoors to amplify weak signals, and then an intermediate device placed in a circle via a coaxial cable. By transmitting the signal to the frequency signal processing section, it has a structure that avoids the influence of noise as much as possible.

The high frequency signal receiving section and the intermediate frequency signal processing section are arranged separately among the circuits that make up the receiving device.
Conventionally, as a method of separating and arranging each circuit, firstly, a circuit part for high-frequency amplification of the received signal is placed in the high-frequency signal receiving section, and a circuit part for converting the frequency of the received signal into an intermediate-frequency signal is placed in the intermediate-frequency signal processing mK. There was a way. however,
According to this method, the frequency of the signal transmitted by the coaxial cable is high, and therefore the amount of attenuation is large, so a high-frequency amplification circuit with a large amplification degree and a thick coaxial cable are required, making the equipment inconvenient to handle and large and expensive. It had the disadvantage of becoming

Further, a second circuit between the high frequency signal receiving section and the intermediate frequency signal processing section
As a separate arrangement method, a mixing circuit as a local oscillation circuit and a frequency conversion circuit is built into the high frequency signal receiving section, and the intermediate frequency signal is transmitted from the high frequency signal receiving section to the intermediate frequency signal processing section. there were. However, this method has the disadvantage that it is not possible to obtain a local oscillation circuit with high frequency stability because the reference signal generation circuit (for example, a crystal oscillator), which is one component of the local oscillation circuit, is installed outdoors where temperature changes are large. Therefore, in order to improve frequency stability, K required a constant temperature bath, etc., making the device complicated and large. In addition, this separation method has the disadvantage that the power consumption of the high frequency signal receiving section becomes large.

In the third separation method, a reference signal generation circuit is placed in the intermediate frequency signal processing section, a multiplier circuit, a PLL (Phase Locked Lp6p) circuit, etc. are placed in the high frequency signal receiving section, and the intermediate frequency signal generating circuit is placed in the high frequency signal receiving section. There is a separation arrangement method in which the frequency of a reference signal given from a frequency signal processing section is multiplied to obtain the local oscillation station number, mixed with a received signal, an intermediate frequency signal is extracted, and the intermediate frequency signal is transmitted to the intermediate frequency signal processing section. there were.

However, in this method, the high-frequency signal receiving section has a multiplier circuit and a PLL circuit, so its volume is large, making it inconvenient to handle, and the parts that require complicated adjustment are exposed outdoors, resulting in low reliability. there were.

[Purpose of the invention]

The present invention has been made in consideration of the above points, and it is an object of the present invention to provide a receiving device for satellite communication that is possible and has good temperature characteristics and high reliability.

[Summary of the invention]

In order to achieve this object, in the present invention, the local oscillation circuit is connected to the intermediate station fL4! The intermediate frequency signal is provided in the high frequency signal receiving section, which is a frequency conversion circuit, and is provided in the high frequency signal receiving section, which is a frequency conversion circuit. The intermediate frequency signal processing section is transmitted through a transmission line from the intermediate frequency signal processing section, making it possible to reduce the size and weight of the section that is handled outdoors, and to allow it to be placed indoors, where high stability and reliability are required. This is what I did.

〔Example〕

Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings. The receiving device shown in FIG. 1 consists of a high frequency signal receiving section 10, an intermediate frequency signal processing section, and one coaxial cable I connecting the high frequency signal receiving section s10 and the intermediate frequency signal processing section.

In the high frequency signal receiving section 10, an antenna 11 receives weak radio waves propagated from an artificial satellite and supplies them to a low frequency high frequency amplification circuit 12. The high frequency amplification signal amplifier amplifies the received signal, extracts only the signal component through the bandpass filter 13, and supplies it to the mixing circuit 14.

The mixing circuit 14 is not a harmonic mixer, and receives the local oscillation signal LO8 given from the local oscillation signal amplification circuit 15,
The mixed output signal tIF is mixed with the high frequency amplified signal RF.
X is applied to the bandpass filter 16. Here, the frequency of the high-frequency amplified signal RF is fRF, and the local oscillation signal LO
If the frequency of 8 is fL, harmonic mixer 1
4, the frequency component element RF of the high frequency amplified signal RF is generally
Since the signal level of is weak, the frequency component mini IPX from the harmonic mixer 14 is 'IFX=I fRyfn - fLl (n is an integer) -
- A mixed output signal IFX represented by (1) is sent out.

Therefore, the bandpass filter 16 uses its output signal IFX
Desired frequency components from mini-F. The intermediate frequency signal IFO is obtained by taking out the intermediate frequency signal IFO, and is applied to the intermediate frequency amplification circuit 17.

Here, the frequency 'IFO of the intermediate frequency signal IFO cannot be selected freely, but the frequency f of the high frequency amplified signal RF.
It is determined by the relationship with R (the frequency of the carrier wave transmitted by the artificial satellite). For example, when the frequency fRF of the high frequency amplified signal RF is 1575 (MHz), the frequency fxa of the intermediate frequency signal IFO. A value of around 75 (MEIz) is appropriate. Frequency f of intermediate frequency signal IFO obtained by one stage of frequency conversion. If you choose too low (e.g. 10
This is because the bandpass filter 13 needs to have extremely steep characteristics that are difficult in practice.

Once the frequency f170 of the intermediate frequency signal IFO is determined, the local oscillation frequency fTJ is an integer multiple of the frequency fTJ, which is the frequency 'RF of the high frequency amplified signal RF and the frequency fF of the intermediate frequency signal IFO. You can decide what the difference will be. As in the above example, the frequency fR is 1575 (Mtlz), and the frequency f
When is 75 (MHz), it is appropriate that the local oscillation frequency fL is 500 (Maz). Local oscillation frequency fL8
If it is made smaller (for example, 100 (M[Lz)), (
1) If n in equation 1 is not large enough to be around 15, the level of the frequency component may become so small that it may not be possible to extract it accurately even through the filter 16, and the local oscillation frequency fL must be increased. Then (for example, 1500 (M
Hz), the amount of attenuation in the coaxial cable I becomes extremely large.

The intermediate frequency amplification circuit 17 amplifies the intermediate frequency signal IFO by an amount corresponding to the amount of attenuation due to the coaxial cable 30, etc., and sends the amplified signal to the coaxial cable I via the demultiplexing/synthesizing circuit 18.

The intermediate frequency signal IFO provided to the intermediate frequency signal processing section B via the coaxial cable 30 is provided to the signal processing circuit B via the single-wave combining circuit 21 in this processing section. The signal processing circuit η is configured to, for example, further frequency convert the intermediate frequency signal IFO and then demodulate it to obtain a data output pata and provide it to the next stage.

The intermediate frequency signal processing section also includes a crystal oscillator and a frequency multiplier circuit constituting a local oscillation circuit, and the frequency of the basic signal 8B formed by the crystal oscillator is multiplied by the frequency multiplier circuit. The local oscillation signal LO8 is generated using the oscillation signal LO8. This local oscillation signal LO8 is amplified to compensate for the amount of attenuation due to the demultiplexing circuit B and the coaxial cable (9), and is then applied to the mixing circuit WR14.

Furthermore, the intermediate frequency signal processing section is also connected to the DC power supply circuit 25.
The operating power supply vCC of each circuit in the high frequency signal receiving section 10 is connected to a demultiplexing and combining circuit 21 and a 30ft coaxial cable.
The signal is supplied to the high-frequency signal receiving section 10 via the high-frequency signal receiving section 10.

As described above, between the high frequency signal receiving section 10 and the intermediate frequency signal processing section, in order to transmit and receive the three signals of the intermediate frequency signal IFO1 local oscillation signal LO8 and the DC power supply vCC, the demultiplexing circuit 18 and 21 are three filters 18a to 18c or 21a to 2 as shown in FIG.
It is composed of 1 ck.

The common terminal TD of each filter 18a to 18c of the demultiplexing/synthesizing circuit 18 is connected to the coaxial cable 30, and the other terminal TA of the filter 18& is connected to the local oscillation signal amplification circuit 15, Another terminal TB is connected to the intermediate frequency amplification circuit 17, and is connected to serve as the other terminal T (J' power supply terminal) of the low-pass filter 18c.

On the other hand, the common terminal TD of the demultiplexing and combining circuit 21 is connected to the coaxial cable I,
The other terminal TA of the bandpass filter 21b is connected to the frequency multiplier circuit, and the other terminal TB of the bandpass filter 21b is connected to the signal processing circuit 2.
2, and the other terminal TC of the filter 4C
is connected to DC power supply circuit B.

In the configuration shown in FIG. 1, the signal captured by the antenna L1 is amplified by the high frequency amplifier circuit 12 and then passed through the band pass filter 13ft to a predetermined frequency, for example 1575 [
Only the high frequency signal component RF having a frequency of Rα2] is extracted and applied to the mixing circuit 14.

This high frequency amplified signal RF is converted into a local oscillation signal L having a frequency of, for example, 500 (M[lz]) in the mixing circuit 14.
1575±n x 500 CMtl mixed with O8
z) mixed output signal IFX with a frequency of (n is an integer)
The signal is subjected to K conversion and provided to a bandpass filter 16)C.

Here, the local oscillation signal LO8 is formed by multiplying the reference signal SB output from the crystal oscillator on the intermediate frequency signal processing side by the multiplier circuit, and
The high frequency signal is applied to the high frequency signal receiver [11S10 side] via the coaxial cable I, and after being amplified by the local oscillation signal amplification circuit W&15, it is applied to the mixing circuit 14.

In the bandpass filter 16)C, an intermediate frequency signal IFO having a predetermined frequency, for example, 75 [2] is extracted from the mixed output signal IFX. After the intermediate frequency signal IFO is amplified by the intermediate frequency amplifying circuit 17, the demultiplexing and combining circuit 1
8. The signal is applied to a signal processing circuit 22 via a coaxial cable and a demultiplexing/combining circuit 21, where the signal is processed and extracted as data output Data. This data output pBt
Based on aK, positioning, reference time detection, etc. are performed in the subsequent stages.

In this way, according to the configuration shown in Fig. 1, the signal to be transmitted is converted into the intermediate frequency signal LO8 and then transmitted via the coaxial cable (to). 10 and an intermediate frequency signal processing section can be combined. In addition, since the crystal oscillator is installed in the intermediate frequency signal processing unit S2O located indoors, it is possible to reduce the effects of temperature fluctuations, create a local oscillation circuit with high frequency stability, and eliminate the need for a constant temperature oven. Therefore, the structure of the high frequency signal receiving section 10 can be made smaller and lighter. Therefore, the high frequency signal receiving section 10 placed outdoors can be easily handled. In addition, according to the configuration shown in FIG. 1, since the multiplier circuit 6 and the like that require adjustment are not provided in the outdoor high-frequency signal receiving section 10, reliability can be improved as described above, and from this point of view, Smaller size and lighter weight can be achieved.

In addition, since the frequency conversion circuit is configured with a mixing circuit 14 and a bandpass filter 16, and a component of a predetermined frequency is extracted from the mixed output signal IFX having many frequency components to obtain an intermediate frequency signal IFO, local oscillation The frequency of the signal LO5 can be selected low, and the attenuation due to the coaxial cable 3o)c can be suppressed to a small amount.

〔Effect of the invention〕

As described above, according to the present invention, the local oscillation circuit is provided in the intermediate frequency signal processing section, the frequency conversion circuit is provided in the high frequency signal receiving section, and the local oscillation signal is transmitted from the intermediate frequency signal processing section to the high frequency signal receiving section. In addition to sending the intermediate frequency signal through the transmission line, the intermediate frequency signal is also sent from the high frequency signal receiving section to the intermediate frequency signal processing section via the transmission line, so the circuit configuration of the high frequency signal receiving section can be easily made and handling is easy. It is possible to provide a satellite communication receiving device that is simple and has the same reliability as above.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of a reception equipment for satellite communication according to the present invention, and FIG. 2 is a block diagram showing the detailed configuration of the demultiplexing/synthesizing circuit. 10... High frequency signal receiving section, 11... Antenna, 1
2...High frequency amplification circuit, 14...Mixing circuit, 16.
. . . band pass filter, addition . . . intermediate station tELM signal processing unit, n . . . signal processing circuit, Z . . . crystal oscillator,

Claims (1)

[Claims] 1. A high frequency signal receiving section provided integrally with an antenna for receiving satellite radio waves, and an intermediate frequency signal processing section connected to the high frequency signal receiving section via a transmission path, The high frequency signal receiving section includes a high frequency amplification stage that amplifies the received signal;
a frequency conversion circuit that converts the amplified output into a predetermined intermediate frequency signal based on a local oscillation signal; the intermediate frequency signal processing section includes a signal processing circuit that processes the intermediate frequency signal; A receiving device for satellite communication, comprising: a local oscillation circuit that supplies the local oscillation signal via the transmission path. 2. The frequency conversion circuit includes a mixing circuit that receives the received signal and the local oscillation signal and outputs a mixed signal having a frequency component obtained by adding or subtracting an integral multiple of the local oscillation signal to the frequency of the received signal; 2. The satellite communication receiving device according to claim 1, further comprising a filter that allows only a predetermined component to pass among the frequency components of the mixed signal and extracts it as the intermediate frequency signal.