JPH0377201A - Satellite broadcasting receiver - Google Patents

Abstract

PURPOSE:To prevent power supplies from two or more power sources to a converter by providing a voltage detecting circuit to detect a voltage superimposed on a cable, and switching the power source on when the voltage detecting circuit does not detect the voltage. CONSTITUTION:In the case that when a power source for a satellite broadcasting receiver B is actuated, a DC voltage for a converter is superimposed on a cable C by another satellite broadcasting receiver connected to the cable C, the voltage superimposed is input to a switching circuit 73 through a gate circuit 72 and a signal to make a switch 6 ON is not output to an output terminal 74. When the DC voltage superimposed on the cable C becomes nil, the voltage input to the switching circuit 73 through the gate circuit 72 also becomes nil and the signal to make the switch 6 ON is output from the switching circuit 73. Consequently, the DC voltage from a power source for converter 3 is superimposed on the cable C so as to supply the voltage to a receiving converter part 2 of an antenna A. The output signal of the switching circuit 73 is fed back to the gate circuit 72 of the voltage detecting circuit 7 and the gate circuit 72 breaks an input voltage so that the voltage on the cable C is prevented from being input to the circuit 7.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a satellite broadcast receiving apparatus that can automatically supply power for a converter.

[Conventional technology]

As shown in Fig. 3, the satellite broadcast receiving system consists of a satellite broadcast receiving antenna device A and a satellite broadcast receiving device B that receives radio waves transmitted from the antenna device A via a cable C and selects a channel. It is configured.

The above-mentioned antenna device A includes a parabolic-shaped radio wave reflector (daytshu) 1 that collects radio waves from a broadcasting satellite, and polarization plane conversion that concentrates the radio waves reflected by the reflector and converts them from circularly polarized waves to linearly polarized waves. inputs the radio waves from the polarization converter and converts it from the 12GH2 band using the hetero gain method.
It has a reception conversion section 2 that includes a down converter for converting to the Cl3 band.

Since this down converter has an internal amplifier and a frequency conversion section, it is necessary to supply a t source from the outside.

Conventionally, a converter power supply 3 is installed in the satellite broadcast receiving device B.
was provided, and by turning on the switch 4, the power was superimposed on the signal cable C and supplied. 5 is a satellite broadcast reception tuner [Problem to be solved by the invention] However, in the communal reception equipment, the same cable C
Since multiple satellite broadcast receivers B are connected to
If power is being supplied to the converter from one of the satellite broadcast receivers B, there is no need for power to be supplied from other satellite broadcast receivers, so the Sui-Nochi 4 is switched manually, and its operation is Not only is this complicated, but the converter may be damaged if the switch 4 is turned on by mistake.

An object of the present invention is to provide a satellite broadcast receiving apparatus that prevents the above-mentioned problems from occurring by preventing power from being erroneously supplied to the converter.

[Means to solve the problem]

To this end, the present invention provides a satellite broadcast receiving device having a power supply for a converter that supplies direct current voltage to a satellite broadcast receiving antenna via a switch and a cable, which is provided with a voltage detection circuit that detects the voltage superimposed on the cable. , the switch is turned on when the voltage detection circuit does not detect a voltage.

In the present invention, the voltage detection circuit can be configured to cut off voltage input to the cable when outputting a signal to turn on the switch.

〔Example〕

Examples of the present invention will be described below. FIG. 1 is a diagram showing internal blocks of a satellite broadcast receiving system according to one embodiment. Components that are the same as those in FIG. 3 are given the same reference numerals. In this embodiment, a normally open switch 6 is connected between the converter power supply 3 and the cable C, and the switch 6 is turned on/off by the voltage detection circuit 7.

This voltage detection circuit 7 detects the DC voltage superimposed on the cable C, and closes the switch 6 when the voltage is zero.

FIG. 2 is a diagram showing an internal block of this voltage detection circuit 7. A gate circuit 72 is provided at an input terminal 71 connected to a cable C, and a switch circuit 73 is operated by a signal outputted from this gate circuit 72. Switch 6 to output terminal 74
Outputs a signal to turn on/off. The output of this switch circuit 73 is fed back to the gate 72.

For example, when power is turned on to satellite broadcast receiver B, if a converter DC voltage is already superimposed on cable C by another satellite broadcast receiver connected to cable C, that voltage The signal passes through the gate 72 and is input to the switch circuit 73, and no signal is output to the output terminal 74 to turn on the switch circuit. In other words, the switch 6 remains off.

Thereafter, when the superimposed DC voltage of the cable C disappears, the voltage input to the switch circuit 73 via the gate 72 disappears, and the switch circuit 73 outputs a signal to turn on the switch 6. As a result, the DC voltage from the converter power source 3 is superimposed on the cable C and is supplied to the reception conversion section 2 of the antenna device A.

At this time, the gate circuit 72 of the voltage detection circuit 7 receives the output signal of the switch circuit 73 (signal for turning on the switch 6).
is feeding back, the gate circuit 72 cuts off the input voltage, and the voltage on the cable C is prevented from inputting to the voltage detection circuit 7.

Therefore, until the power of the satellite broadcast receiving device B in which the voltage detection circuit 7 is incorporated is turned off, the converter power supply 3
continues to be supplied to the reception conversion section 2 of the antenna device A.

〔Effect of the invention〕

As described above, according to the present invention, power is automatically supplied only when power is not supplied to the cable connected to the converter of the antenna device, thereby preventing power from being supplied to the converter from two or more sources. The advantage is that it can be done.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a satellite broadcast receiving system according to an embodiment of the present invention, FIG. 2 is a block diagram of a voltage detection circuit, and FIG. 3 is a block diagram of a conventional satellite broadcast receiving system. A... Satellite broadcast receiving antenna device, B... Satellite broadcast receiver, C... Cable, 1... Radio wave reflector, 2
... Reception conversion section, 3... Power supply for converter, 4...
・Switch, 5...Satellite broadcast reception tuner, 6...
Switch, 7...voltage detection circuit.

Claims (2)

[Claims] (1). In a satellite broadcast receiving device having a power supply for a converter that supplies DC voltage to a satellite broadcast receiving antenna via a switch and a cable, a voltage detection circuit is provided to detect the voltage superimposed on the cable, and the voltage detection circuit detects the voltage. A satellite broadcast receiving device characterized in that the above switch is turned on when the above switch is not detected. (2). 2. The satellite broadcast receiving apparatus according to claim 1, wherein said voltage detection circuit cuts off voltage input to said cable when outputting a signal for turning on said switch.