KR960002667B1 - Duplex frequency transfer - Google Patents

Abstract

The circuit for controlling DC bias of IF amplifier to increase reliability of horizontal/vertical separation in satellite broadcast receiver includes amplifiers(23,24) amplifying horizontal/vertical signal received from receiver to high frequency one, mixers(25,26) mixing amplified signals and local oscillated signal to provide IF frequency, n X n switching circuit(30) providing n outputs selectively after receiving n inputs of horizontal/vertical IF frequency signal, and receivers(28,29) receiving n outputs.

Description

Horizontal / Vertical Switching Circuit of Multiple Frequency Converter (LNB)

1 is a conventional circuit configuration diagram.

2 is an overall circuit diagram of the present invention.

3 is a detailed circuit diagram of an n × n switching circuit of the present invention.

4 is a detailed configuration diagram of the voltage detection circuit of the present invention.

5 is a diagram showing an operation of an n × n switching circuit of the present invention.

* Explanation of symbols for main parts of the drawings

23,24: amplifier 25,26: mixer

27: oscillator 28,29: receiver

30: n × n switching circuit 31 to 36 amplifier

40,50: Voltage detection circuit L: Choke coil

41: Zener Diode 42,43: Inverter

Q ₁ , Q ₂ : transistor

The present invention relates to a primary frequency-converted intermediate frequency (IF) signal switching circuit in a plurality of LNBs in which two or more satellite broadcasting receivers independently select horizontal and vertical signals freely, and in particular, direct current of an IF amplifier. The present invention relates to a horizontal / vertical switching circuit of a plurality of LNBs in which horizontal / vertical isolation and operation reliability are improved by appropriately controlling bias.

In the prior art, as illustrated in FIG. 1, the vertical intermediate frequency (V _1F ) signal 1 and the horizontal intermediate frequency (H _HF ) signal 2, which are transitioned to the 900-2000 MHz frequency band, include the first amplifier 3. 4 are amplified and amplified and then divided into two and output to the diode switching circuits 5 and 6, respectively.

The diode switching circuit (5) (6) is composed of a plurality of diode signal lines, the passage is controlled by the voltage detection circuit (9) 10 in accordance with the 18V / 14V DC voltage applied from an external receiver On / off.

The outputs of the diode switching circuits 5 and 6 are applied to the second amplifiers 7 and 8 and amplified, respectively. In this case, each diode switching circuit 5 and 6 has a vertical signal V ₁ (V ₂ ). ) And only one of the horizontal signals H ₁ and H ₂ is amplified.

Accordingly, the second amplifier 7 selects and outputs either the vertical signal V ₁ or the horizontal signal H ₁ , and the second amplifier 8 outputs the vertical signal V ₂ or the horizontal signal H. ₂ ) Select and output one of them.

In this way, the horizontal / vertical signals are switched and selected.

This conventional technique requires complicated circuit configuration because three to four diodes must be used for each diode line in order to improve vertical separation, and a current of at least 20 mA is required to turn on / roof a large number of diodes in each diode line. Since it needs to be opened and closed, current consumption increases, and additional resistance elements and coils for controlling the on / off of each diode must be additionally configured. Therefore, the complexity of the circuit is intensified. Many problems occur, such as a loss of signal.

Accordingly, the present invention has been made to solve the above-mentioned problems, the object of the present invention is to simplify the circuit by operating amplification means by eliminating a number of conventional diode lines, only the amplifier required for circuit operation By minimizing the current consumption by operating, the DC bias of the IF amplifier is properly controlled to provide a horizontal / vertical vertical switching circuit of a plurality of LNBs which greatly improves the separation of the horizontal / vertical signals.

The technical configuration for achieving the object of the present invention, the vertical and horizontal high frequency amplification unit for receiving a high frequency amplification of the vertical and horizontal signals of the satellite broadcast signal, and the vertical and horizontal high frequency amplified signal and the local oscillation signal of the oscillator Vertical and horizontal mixers for mixing to make the intermediate frequency, n × n switching circuit and the switching circuit of receiving the vertical and horizontal intermediate frequency signal as n input and switching by amplifying means and transistor logic to selectively output n output First and second receivers for receiving the n output, respectively, characterized in that to improve the separation of the vertical and horizontal signals and the reliability of the operation.

The n × n switch circuit may include a vertical and horizontal IF amplifier for amplifying vertical and horizontal intermediate frequency signals, and a first vertical signal V ₁ and a second vertical signal V _{2 among} the IF amplified vertical signals. A V ₁ amplifier and a V ₂ amplifier for amplifying, an H ₁ amplifier and H ₂ amplifier for amplifying a first horizontal signal H ₁ and a second horizontal signal H _{2 among} the IF amplified horizontal signals, and an input / output with an external device And a voltage detection circuit operated by vertical and horizontal control voltages input through lines (a) and (b) to selectively turn on / off the V ₁ , V _2, and H ₁ , H ₂ amplifiers. The voltage detection circuit includes a choke coil for passing only a plurality of d and c voltages passing through the input / output lines (a) and (b), a zener diode operating on / off according to a plurality of d and c voltages passing through the coil; First and second inverters for inverting a pass voltage of the zener diode, and And a second transistor for controlling the V ₁ amplifier operating according to the output of the first inverter, and a first transistor for controlling the H ₁ amplifier by operating according to the output of the H ₁ second inverter. It is done.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

2 is a circuit configuration diagram of the present invention, wherein the vertical signal and the horizontal signal polarization are vertical signal RF amplifier 23 and horizontal signal RF amplifier 24 through the vertical signal input terminal 21 and the horizontal signal input terminal 22. Connect to apply.

In the vertical / horizontal signal RF amplifiers 23 and 24, the respective RF signals are low noise amplified and connected to the vertical signal mixer 25 and the horizontal signal mixer 26, respectively.

The vertical / horizontal signal mixers 25 and 26 mix the low-noise amplified vertical / horizontal RF signal with the local oscillation signal of the oscillator 27 to produce a vertical / horizontal intermediate frequency (IF) and then input 2 × 2 outputs. It is input to the switching circuit 30.

The two input by two output switching circuit 30 is shown in detail in FIG. 3, which will be described later in detail.

The vertical / horizontal signals switched by the switching circuit 30 are input to the first receiver 28 and the second receiver 29, respectively.

Here, the first receiver 28 and the second receiver 29 are the final outputs of the twin LNBs.

At this time, the two input and output signals (a) and (b) input and output from the switching circuit 30 are vertical regardless of the output signals corresponding to each other, i.e., the b output signal corresponding to the a output or the a output signal relative to the b output signal. The switching circuit 30 should be operated so that the horizontal signal is freely selected.

For this purpose, a DC power supply of 18V and 14V for the vertical signal and the horizontal signal from the first receiver 28 and the second receiver 29 is respectively applied to the first voltage detection circuit 40 and the second voltage detection circuit of FIG. Must be entered at 50.

Here, a horizontal signal is received with respect to the 18V, and a vertical signal is received with respect to the 14V. 3 will be described below.

The intermediate frequency signal input from the vertical signal mixer 25 and the horizontal signal mixer 26 is amplified to a constant signal level by the vertical IF amplifier 31 and the horizontal IF amplifier 32.

The vertical signal amplified by the vertical IF amplifier 31 is divided into a first vertical signal V ₁ and a second vertical signal VF ₂ through a capacitor C ₁ , and then each of the V ₁ amplifiers 33 and It is input to the V ₂ amplifier 35.

The horizontal signal amplified by the horizontal IF amplifier 32 is divided into a first horizontal signal H ₁ and a second horizontal signal H ₂ through a condenser C ₃ , and then each H ₁ amplifier 34 and It is input to the H ₂ amplifier 36.

The signal a amplified by the V ₁ amplifier 33 and the H ₁ amplifier 34 is input to the first receiver 28 through a capacitor C ₂ , and the V ₂ amplifier 35 and H _2. The signal b amplified by the amplifier 36 is input to the second receiver 29 through the capacitor C ₄ .

At this time, a DC power of 18V / 14V is input through each of the signal (a) and (b) lines, and this DC power is supplied through a coil (L ₁ ) (L ₂ ) and a capacitor (C ₅ ) (C ₆ ). Input to the first voltage detection circuit 40 and the second voltage detection circuit 50, respectively.

The first and second voltage detection circuits 40 and 50 are shown in detail in FIG.

The first voltage detection circuit 40 detects a signal level difference of 18 V or 14 V input through the signal line a and is applied to the V ₁ amplifier 33 and the H ₁ amplifier 34. The bias is turned on and off, and the second voltage detection circuit 50 senses a signal level difference of 18 V or 14 V input through the signal line b to detect the V ₂ amplifier 35 and the H ₄ amplifier ( On and off control the d, c bias applied to 36).

For example, when the voltage applied in (a) is 18V, the horizontal signal must be received and the bias is cut off, and the bias of the H ₁ amplifier 34 is applied to the amplified signal input from the horizontal signal mixer 26. After the amplification in the H ₁ amplifier 34 to be output.

On the other hand, if the voltage applied in (a) is 14V, since the vertical signal must be received, the bias of the H ₁ amplifier 34 is cut off and the bias of the V ₁ amplifier 33 is applied to the vertical signal mixer 25. The signal amplified from the amplified signal is output after being amplified by the V ₁ amplifier 33.

This operation principle is equally applied to the V ₂ amplifier 35 and the H ₂ amplifier 36 by the 18V / 14V voltage applied in (b).

4 is a detailed view of the first and second voltage detection circuits 40 and 50. When d and c voltages of 18 V / 14 V are input in (a), the d and c voltages are (a). It is entered in the direction of the arrow.

The d and c voltage input signals are applied to the zener diode 41 input side via the choke coil L.

At this time, since the coil L is designed to have a sufficiently large impedance with respect to the a and c signals output from the V ₁ amplifier 33 and the H ₁ amplifier 34, the coil L has little effect on the a and c output signals. .

When the 18V / 14V d and c voltages applied to the zener diode 41 are 18V, the zener diode 41 is turned on, but when the d and c voltages are 14V, the zener diode 41 is cut off.

Accordingly, the voltage V _R applied to the resistor R becomes high at 5V when the voltage is 18V, but becomes 0V when the voltage is 14V, and the first and second logic inverters 42 and 43 are the same as those of FIG. 5. Indicates a logic state.

That is, when the horizontal (H) signal is received, since the (a) voltages d and c through the input terminal are 18V, the zener diode 41 is turned on, and the high signal 5V is applied to the first inverter 42.

Accordingly, the output of the first inverter 42 becomes low (0V) to turn off the transistor Q ₂ , and this low signal becomes a high signal again through the second inverter 43 to make the transistor Q ₁ . Turn on.

Since the transistor Q ₂ is off, the V ₁ amplifier 33 is also off, and the transistor Q ₁ is on, so the H ₁ amplifier 34 is also on.

In this way it becomes a level signal received, because the H ₁ amplifier 34 is turned on. On the contrary, when the vertical (V) signal is received, since the voltages d and c through the input terminal (a) are 14V, the zener diode 41 is turned off, and the low signal (0V) is applied to the first inverter 42.

Accordingly, the output of the first inverter 42 becomes high (5V) to turn on the transistor Q ₂ , and this high signal becomes a low signal again through the second inverter 43 to make the transistor Q Turn off ₁ ).

Since the transistor Q ₂ is on, the V ₁ amplifier 33 is on, and the transistor Q ₁ is off, so the V ₁ amplifier 33 is on.

As such, since the V ₁ amplifier 33 is turned on, a vertical signal is received. This operation is equally applied to both the first and second voltage detection circuits 40 and 50.

As described in detail above, in the present invention, since at least 12-16 diodes are eliminated as compared to a technology of turning on / off a signal line composed of a plurality of diodes, the circuit is simplified, so that the reliability of the operation is improved. Current consumption is reduced by 10-12㎃ because only the required amplifier is operated, and the separation of horizontal and vertical signal lines, which are prone to appear due to signal loss due to forward resistance during diode operation and reverse capacitance when diode off, can be prevented. It can have an excellent effect.

Claims (3)

Vertical and horizontal high frequency amplification units 23 and 24 for receiving high frequency vertical and horizontal signals among satellite broadcast signals and local oscillation signals of the vertical and horizontal high frequency medium width signals and the oscillator 27 are mixed to make intermediate frequencies. Main and horizontal mixers 25 and 26, n × n switching circuits 30 which receive the vertical and horizontal intermediate frequency signals as n inputs and selectively output n output signals by amplifying means and transistor logic; First and second receivers 28 and 29 respectively receiving n outputs of the switching circuit to improve vertical and horizontal signal separation and operation reliability of the plurality of LNB. Circuit. The switching circuit of claim 1, wherein the n × n switching circuit 30 includes vertical and horizontal IF amplifiers 31 and 32 for amplifying vertical and horizontal intermediate frequency signals, and a first vertical signal V among the IF amplified vertical signals. ₁ ) and a V ₁ amplifier 33 and a V ₂ amplifier 35 for amplifying the second vertical signal V ₂ , and a first horizontal signal H ₁ and a second horizontal signal H among the IF amplified horizontal signals. ₂ ) amplified by the H ₁ amplifier 34 and H ₂ amplifier 36 to amplify and the vertical and horizontal control voltage input through the input and output lines (a) and (b) to the outside to the V ₁ , V ₂ And a voltage detection circuit (40) (50) for selectively turning on and off the H ₁ and H ₂ amplifiers (33 to 36). 3. The voltage detecting circuit (40) (50) according to claim 2, wherein the voltage detecting circuit (40) (50) includes a choke coil (L) for passing only a plurality of d and c voltages passing through the input / output lines (a) and (b), and a plurality of passing through the coil. Zener diodes 41 that are turned on and off in response to voltages d and c, first and second inverters 42 and 43 for inverting a pass voltage of the zener diodes, and outputs of the first inverters. a second transistor (Q _2), a first transistor including (Q ₁₎ that controls said H ₁ amplifier 34 to operate in accordance with the output of the second inverter which operates by controlling the V ₁ amplifier 33 Switching circuit, characterized in that made.