JP2001237601A - Satellite switcher and satellite receiving system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a satellite receiving system equipped with a satellite switcher wherein circuit design is facilitated and the number of parts is reduced. SOLUTION: A satellite switcher 1 for selecting received signals from two CS antennas 2a and 2b and transmitting any signal to a receiving terminal is formed by providing a shield case with two signal input terminals 16a and 16b and one signal output terminal 17. A relay 18 for switching input signals is provided inside, and a pulse signal blocking circuit 15 composed of the parallel circuit of a first choke coil L1 and a capacitor C1 is interposed between the input and output terminals. The signal output terminal 17 is provided with a second choke coil L2 for making a pulse signal pass and a third choke coil L3 for making a DC current pass and these choke coils are respectively connected to a pulse signal detecting circuit 19 and a constant voltage power source circuit 20.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a satellite receiving system for transmitting received signals from one satellite to a receiving end by switching received signals from a plurality of satellites by satellite selecting means provided in the middle of a signal transmission path. In particular, it relates to improvement of the satellite selection means.

[0002]

2. Description of the Related Art With the start of CS digital broadcasting, a plurality of CS satellites transmitting radio waves in overlapping frequency bands, for example, J
CSAT-3 and JCSAT-4 have been launched.
Therefore, when the radio waves of those satellites are drawn indoors and received by one signal transmission path, the reception antenna is switched in the middle of the signal transmission path from the receiving antenna to a receiving device such as a tuner provided at the receiving end. Satellite selecting means for selecting a signal from any one of the antennas and transmitting the selected signal to the receiving end is provided.

[0003] Such a satellite selecting means (satellite switch) has a configuration disclosed in Japanese Patent Application Laid-Open No. H11-298355. This is, as shown in FIG. 6, a tuner connection terminal 31 and two satellite reception antenna connection terminals 32a and 32b.
And a switch C33, which is connected by switching with a changeover switch 33. In order to separate the received signal from the converter operating current and the antenna switching signal, a capacitor C11 is provided in series on the signal transmission line and is connected in parallel with the capacitor C11.
The choke coils L11, L12, L13 are connected. Further, a tone signal, which is a switching signal, is extracted through the choke coil L11. In FIG. 6, reference numeral 34 denotes a tone signal detection circuit, 35 denotes a changeover switch drive circuit, and 36 denotes a power supply stabilization circuit.

[0004]

However, in the case of the above configuration, the tone signal can be taken out of the signal transmission line and the changeover switch 33 can be switched. However, one capacitor C11 and three choke coils L11, L1
Since the characteristics of the separation circuit composed of L2 and L13 are related to each other, circuit design is difficult, and two capacitors C12 and C13 for grounding the interconnection point of the choke coil are required. In view of the above problems, it is an object of the present invention to provide a satellite receiving system provided with a satellite switch in which circuit design is easy and the number of parts is reduced.

[0005]

In order to solve the above-mentioned problems, a satellite switch according to the present invention selects a signal received from a plurality of satellite receiving antennas for receiving a satellite signal and selects one of the signals. A satellite switch for transmitting a signal from an antenna to a receiving end, the switching operation being performed by a selection signal sent from the receiving end, and a plurality of signal input terminals for inputting a received signal from the satellite receiving antenna and one signal Switching means for switching a reception signal output from the signal output terminal in a shield case having an output terminal, and switching means for detecting the selection signal sent from the reception end via the signal output terminal, and Signal detecting means for operating the antenna, and further including an upstream operating current for operating a converter provided on the antenna in the middle of a reception signal transmission path in the shield case. A blocking circuit comprising a parallel circuit of a capacitor for blocking the passage of the selection signal and the first choke coil is provided, and a signal output terminal allows the passage of the selection signal and the passage of the reception signal to the signal detection means. A second choke coil for supplying a selection signal is connected.

According to a second aspect of the present invention, in the first aspect, the selection signal is a pulse signal of 35 kHz to 53 kHz.

A satellite receiving system according to a third aspect of the present invention includes a plurality of satellite receiving antennas for receiving satellite signals, and a signal from any one of the plurality of antennas is selected and transmitted to a receiving end. What is claimed is: 1. A satellite receiving system comprising: a satellite selecting unit provided in the middle of a signal transmission path, wherein said satellite selecting unit includes: a signal detecting unit that detects a selection signal sent from a receiving end; Switching means for switching received signals from a plurality of antennas by a signal, and a capacitor for passing an operating current in an upward direction for operating a converter provided in the antenna and for preventing passage of the selection signal in the middle of a received signal transmission path. And a first choke coil in parallel with a blocking circuit, and a signal detection means for passing a selection signal and blocking a reception signal. Characterized by comprising a second choke coil for supplying a selection signal.

According to a fourth aspect of the present invention, in the third aspect, the selection signal is a pulse signal of 35 kHz to 53 kHz.

[0009]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a block diagram showing an example of a satellite receiving system according to the present invention.
2 (2a, 2b) is, for example, JCSAT-3 or JCSAT
-1A receiving the first CS receiving antenna and the second C receiving antenna
The S receiving antenna receives vertical and horizontal polarized waves, respectively, performs IF conversion by a built-in converter, and outputs the received signal through two coaxial cables. Each signal is amplified by the CS boosters 3a and 3b and connected to two independent CS polarization switching distributors 4 (4a and 4b) to divide the signals into four. Also, this polarization switching distributor 4
, Terrestrial broadcasts received by VHF and UHF antennas 6 and 7 and BS broadcasts received by BS antenna 8 are also distributed by distributor 9 and input.

The CS polarization switching distributor 4 has a function of switching between horizontal polarization and vertical polarization of the received CS signal and transmitting either signal to the receiving end.
The BS broadcast is also superimposed and transmitted. And CS
Each output of the polarization switching distributor 4 is connected to a television terminal 10 provided at a receiving end via a satellite switching device 1 as a satellite selecting means, and an operation signal of the satellite switching device 1 is transmitted to the television terminal 10. CS tuner 12, video 13, and BS
The built-in television 14 and the like are connected. The CS polarization switching distributor 4 and the satellite switching device 1 operate by a signal transmitted from the receiving end via a signal transmission path.
The switching operation of the satellite switch is performed by switching the DC voltage value of the operating current for operating the converter provided in the S antenna to, for example, 11 / 15V.
This is performed depending on the presence or absence of a pulse signal of kHz.

The satellite switch 1 will be described with reference to the circuit block diagram of FIG. Reference numerals 16a and 16b denote signal input terminals for receiving received signals, and reference numeral 17 denotes a signal output terminal. The output terminal 17 is connected to one of the signal input terminals via a high-frequency compatible relay 18. Between the relay 18 and the signal input terminal, a pulse signal blocking circuit 15 in which a first choke coil L1 and a capacitor C1 are connected in parallel is interposed to pass both the satellite reception signal in the down direction and the converter operating current in the up direction. , And block the passage of the satellite switching signal. The signal output terminal 17 is connected via a second choke coil L2 to a pulse signal detection circuit 19, which is a signal detection means for detecting a satellite switching signal.
0 is connected via the third choke coil L3. The second choke coil L2 blocks passage of a high-frequency signal, which is a transmission signal from the antenna, and the third choke coil L3 blocks passage of a high-frequency signal and a pulse signal.

The pulse signal detection circuit 19 is a circuit for detecting a pulse signal sent from the receiving end and controlling a relay drive circuit 21 for operating the relay 18, and performs a switching operation depending on the presence or absence of the pulse signal. The low-voltage power supply circuit 20 uses the converter operating current sent from the receiving end to generate a constant voltage and supply power to the pulse signal detection circuit 19 and the relay drive circuit 21.

By using such a circuit for the satellite switch, the first to third choke coils having independent characteristics can be used, and the circuit can be easily designed. In particular, since the first choke coil is independent, a good combination with a capacitor can be easily selected. Further, the number of capacitors can be reduced to one, and the number of elements can be reduced. Furthermore, if the satellite selection signal is 35 kHz to 53 kHz as described above, the selection signal does not pass through the first choke coil L1 to cause noise due to modulation, and passes through the capacitor C1 to cause noise due to modulation. It does not cause noise.

The external appearance of the satellite switch is formed by a shield case 23 as shown in FIG. 3, and has two signal input terminals 16a and 16b on one side and one signal output terminal 17 on the opposite side. In each case, an F-type plug is used. The shield case 23 can be formed by die-casting using, for example, an alloy of aluminum or copper and zinc, and has an interference rejection capability of 100 dB to 110 dB at 1 GHz.
Those having about B are preferable.

The CS tuner 12 connected to the television terminal has a satellite selection switch, and generates a pulse signal by operating this signal selection switch to switch the satellite switch 1. The CS tuner also supplies power to the converter and the BS antenna provided in the CS antenna and outputs a DC voltage of 11/15 V for switching the reception polarization of the CS radio wave. In the case of this embodiment, the number of satellites to be switched is two. However, if the number of input parts of the satellite switch is three and any one of them is selected, three antennas can be switched and received. Yes, the number of selections can be further increased, and an arbitrary number of inputs can be easily switched. In this case, the switching signal can be easily switched by changing the frequency or the amplitude. Further, the pulse signal may be a tone signal. As described above, even if there are a plurality of satellites having overlapping frequency bands, it is possible to easily select and receive those satellite signals by operation from the receiving end.

FIG. 4 shows another example of the circuit of the satellite switch, which is different from the above embodiment in the connection of the power supply circuit. Third
Is connected to the signal output terminal 17 via the second choke coil L2, and the connection point of the second and third choke coils is grounded via the capacitor C2. The third choke coil L3 may be connected in this way.

Further, the satellite switch can be built in the CS polarization switch distributor. In this case, the satellite receiving system has a configuration as shown in FIG.
The S-polarization switching distributor 24 has four signal input terminals for inputting signals from two CS satellites and one signal input terminal for inputting terrestrial broadcast and BS broadcast. The four signal output terminals are The coaxial cable is directly connected to each of the television terminals 10 serving as a receiving end. In this way, if the satellite switch is built in the CS polarization switching distributor, the number of CS polarization switching distributors can be reduced to one, and the output can be connected simply by directly connecting the output to the terminal. It can be simplified.

[0018]

As described above in detail, according to the first or third aspect of the present invention, a blocking circuit for passing a satellite reception signal and a DC current and blocking a selection signal for selecting a satellite is provided with a capacitor. And the first choke coil are formed in parallel, and provided independently of the other second and third choke coils, so that each coil can have independent characteristics.
The circuit design of the satellite switch and the satellite selection means can be easily performed. Further, the number of elements forming a circuit can be reduced.

According to the invention of claim 2 or 4, claim 1 is provided.
In addition to the effects of the third aspect, it is easy to select a power supply and a selection signal, and there is no possibility of causing noise due to modulation.

[Brief description of the drawings]

FIG. 1 is a block diagram of a satellite receiving system showing an example of an embodiment of the present invention.

FIG. 2 is a circuit block diagram of the satellite switch of FIG. 1;

FIG. 3 is a perspective view showing an appearance of the satellite switch of FIG. 2;

FIG. 4 is a circuit diagram showing another embodiment of the satellite switch.

FIG. 5 is a block diagram showing another embodiment of the satellite receiving system.

FIG. 6 is a circuit block diagram of a conventional satellite selecting means.

[Explanation of symbols]

1. Satellite switcher (satellite selection means), 2. CS antenna, 4 CS polarization switcher, 6 VHF antenna, 7 UHF antenna, 8 BS antenna, 10
··· TV terminal, 12 ·· CS tuner, 15 ··· Pulse signal blocking circuit (blocking circuit), 16 ··· Signal input terminal,
17. Signal output terminal, 18 Relay (switching means),
19 ·· Pulse signal detection circuit (signal detection means), 24 ·
.CS polarization switching distributor, C1..condenser, L1 ..
A first choke coil, L2... A second choke coil, L3.

Claims (4)

[Claims] A satellite switch for selecting a received signal from a plurality of satellite receiving antennas for receiving a satellite signal and transmitting a signal from any one of the antennas to a receiving end, wherein the satellite switch is transmitted from the receiving end. A switching operation is performed in response to an incoming selection signal to switch a reception signal output from the signal output terminal into a shield case having a plurality of signal input terminals for inputting a reception signal from a satellite reception antenna and one signal output terminal. Means, and a signal detecting means for detecting the selection signal sent from the receiving end via the signal output terminal and activating the switching means, and further in the middle of the received signal transmission path in the shield case, From a parallel circuit of a capacitor and a first choke coil, which passes an upward operating current for operating a converter provided in the antenna and prevents the selection signal from passing therethrough. And a signal output terminal for supplying the selection signal to the signal detection means while passing the selection signal and preventing the reception signal from passing therethrough.
A satellite switch, wherein a choke coil is connected. 2. The satellite switch according to claim 1, wherein the selection signal is a pulse signal of 35 kHz to 53 kHz. 3. A plurality of satellite receiving antennas for receiving satellite signals, and a satellite selector provided in the middle of a signal transmission path for selecting a signal from any one of the plurality of antennas and transmitting the selected signal to a receiving end. A satellite receiving system having means for detecting a selection signal sent from a receiving end, and detecting signals received from a plurality of antennas by the detection signals of the signal detecting means. A switching circuit for switching, and a parallel circuit of a capacitor and a first choke coil in the middle of a reception signal transmission path, the capacitor being configured to pass an upward operating current for operating a converter provided in the antenna and to prevent the selection signal from passing therethrough. And a second choke coil for supplying the selection signal to the signal detection means by passing the selection signal and blocking the reception signal. And a satellite receiving system comprising: 4. The satellite receiving system according to claim 3, wherein the selection signal is a pulse signal of 35 kHz to 53 kHz.