KR20000061021A - Circuit for attenuating receive signal of mobile station - Google Patents

Abstract

PURPOSE: A circuit for attenuating a receiving signal of a mobile communication terminal is provided for decreasing a receiving signal using a common amplification and attenuating operation of an electric field effect transistor and decreasing the level of a receiving signal. CONSTITUTION: When a receiving signal is inputted into a receiver of a mobile communication terminal, a first condenser(100) transmits an alternating current component from which a direct current component is removed. A second condenser(200) removes a noise of an attenuating control signal outputted from a controller. A first switching unit(300) is turned on when an attenuating control signal from the second condenser(200) is a high signal and is turned off when the attenuating control signal is a low signal. In addition, A second switching unit(500) is turned on when an attenuating control signal from the third condenser(400) is a high signal and is turned off when the attenuating control signal is a low signal.

Description

CIRCUIT FOR ATTENUATING RECEIVE SIGNAL OF MOBILE STATION}

The present invention relates to a reception signal attenuation circuit of a mobile communication terminal receiver, and more particularly, to a reception signal attenuation circuit of a mobile communication terminal capable of controlling an attenuation amount of a reception signal by using an amplification and attenuation action which is a general characteristic of a field effect transistor. will be.

As shown in FIG. 1, the reception signal attenuation circuit of the conventional mobile communication terminal receiver includes a first condenser 1 for removing only a DC component and transmitting only an AC component when a received signal is input to the mobile communication terminal, and the first capacitor. The amplification unit 2 amplifies and transmits the received signal of the AC component transmitted through the condenser 1 to a predetermined level, and the attenuation value is high / high by the control signal of a controller (not shown) according to the input level of the received signal. The second condenser 3, which removes noise when inputted as a low signal, the third condenser 4 having the same function as the second condenser 3, and the second condenser 3, A first inverter 5 that receives a high / low signal of attenuation value and converts it into a low / high signal, and a second / high signal that converts the low / high signal transmitted from the first inverter 5 into a high / low signal. 2 inverter 6 and said 1st, 2nd A first attenuator 7 receiving the signal transmitted through the butters 5 and 6 and attenuating the received signal amplified by the amplifier 2 to a predetermined level, and the third condenser 4 A third inverter 8 that receives the high / low signal of the attenuation value transmitted through the high / low signal and converts the low / high signal transmitted through the third inverter 8 into a high / low signal The fourth inverter 9 converts the signal to the fourth inverter 9, and receives the signals transmitted through the third and fourth inverters 8 and 9. The received signal amplified by the amplifier 2 is transmitted to a predetermined level. A second condenser 10 to attenuate, a fourth capacitor 11 mounted between the first and second attenuators 7 and 10 to transmit a signal of an alternating current component having a DC component removed therefrom; A fifth signal receiving the signal transmitted through the second attenuator 10 and transmitting a signal of an AC component from which a DC component is removed; It consists of a condenser (12).

That is, in the operation process of the conventional mobile communication terminal reception signal attenuation circuit, when the reception signal is input to the reception unit of the mobile communication terminal (not shown), the first condenser 1 transmits a signal of an AC component from which a DC component is removed, and amplifies the signal. The unit 2 receives the received signal of the AC component transmitted through the first capacitor 1 and amplifies and transmits the received signal.

At this time, if the received signal level amplified by the amplifier 2 is amplified above a predetermined level, the attenuation value set in order to attenuate the level of the received signal amplified by the controller (not shown) corresponds to 12dB or 24dB. Send a low signal.

That is, in order to attenuate the level of the received signal amplified by the amplifier 2 by 24 dB, the control unit transmits a high signal corresponding to the attenuation of 24 dB, and the second capacitor 3 transmits the attenuation value transmitted from the controller. It removes the noise included in the attenuation value and receives the input.

Then, the first inverter 5 receives the high signal transmitted through the second condenser 3, converts the signal into a low signal, and transmits the converted high signal from the first inverter 5 from the first inverter 5. The low signal is converted into a high signal and transmitted.

Subsequently, the first attenuator 7 reduces the level of the received signal amplified by the amplifier 2 by the low / high signals transmitted through the first and second inverters 5 and 6. That is, the received signal is attenuated at a level of 24 dB.

In addition, in order to amplify the received signal amplified by the amplifier 2 to a predetermined level or more and attenuate it to a level of 12 dB, the control unit transmits a high signal corresponding to 12 dB, and the third condenser 4 to the controller. After removing the noise included in the attenuation value transmitted from the transmission.

Then, the third inverter 8 receives the high signal transmitted through the third capacitor 4, converts the signal into a low signal, and transmits the converted high signal from the third inverter 8 from the third inverter 8. Receives the low signal and converts it into a high signal and sends it.

Subsequently, the second attenuator 10 reduces the level of the received signal amplified by the amplifier 2 by the low / high signals transmitted through the third and fourth inverters 8 and 9. That is, the received signal is attenuated at a level of 12 dB.

In addition, the fourth capacitor 11 is mounted between the first attenuator 7 and the second attenuator 10 to remove the DC component included in the received signal transmitted from the first attenuator 7. After the transmission to the second attenuator 10, the fifth capacitor 12 removes the DC component included in the received signal transmitted through the second attenuator 10 and then receives the received signal of the AC component. Send it.

On the other hand, when the level of the received signal amplified by the amplifier 2 is amplified to a predetermined level or less, the first and second attenuators 7 and 10 do not attenuate the level of the received signal by the controller. The low signal is applied to the third inverters 5 and 8 so as not to attenuate the level of the received signal.

However, the conventional mobile communication terminal reception signal attenuation circuit as described above uses a large number of transistors, diodes, and inverters to attenuate to a predetermined level when a received signal is input, resulting in a high number of components in circuit design, resulting in increased cost. Since the area is wide, there is a problem that the terminal can not be miniaturized and lightweight.

Accordingly, an object of the present invention is to solve the conventional problems as described above, and an object of the present invention is to reduce the level of a received signal by using general amplification and attenuation characteristics of a field effect transistor. To provide an attenuation circuit.

In order to achieve the above object, the present invention provides a mobile communication terminal reception signal attenuation circuit, comprising: a first condenser for transmitting an AC component from which a DC component is removed when a reception signal is input to a reception unit of the mobile communication terminal; A second capacitor for removing noise of the attenuation control signal transmitted from the control unit; A first switching unit turned on when the attenuation control signal transmitted through the second capacitor is a high signal, and turned off when a low signal; A third condenser for removing noise of another attenuation control signal of the controller; A second switching unit turned on when the attenuation control signal transmitted through the third capacitor is a high signal, and turned off when a low signal; A voltage divider configured to determine collector voltages of the first and second switches; A fourth capacitor for removing noise included in the attenuation value transmitted through the voltage divider; The received signal transmitted through the first capacitor is inputted from the first gate pin, and the high or low signal of the attenuation value transmitted through the fourth capacitor is inputted from the second gate pin and attenuated according to two input signal differences. A field effect transistor configured to determine and attenuate correspondingly the received signal of the mobile communication terminal; A noise removing unit for removing noise included in a received signal attenuated or amplified by the field effect transistor; And an impedance matching unit for preventing a voltage from being lost when the received signal transmitted from the field effect transistor is input to the other circuit.

1 is a circuit diagram showing a conventional mobile communication terminal reception signal attenuation circuit;

2 is a circuit diagram showing a mobile communication terminal received signal attenuation circuit according to an embodiment of the present invention;

3 is a view showing characteristics of a field effect transistor in a mobile terminal receiving signal attenuation circuit according to an embodiment of the present invention;

4 is a table showing a gain value according to the input of the field effect transistor in the mobile terminal receiving signal attenuation circuit according to an embodiment of the present invention.

<Description of the code | symbol about the principal part of drawing>

100: first capacitor 200: second capacitor

300: first switching unit 310: first resistor

320: second resistor 330: first transistor

400: third capacitor 500: second switching unit

510: third resistor 520: fourth resistor

530: second transistor 600: voltage divider

700: fourth capacitor 800: field effect transistor

900: noise removing unit 1000: impedance matching unit

Hereinafter, the above-described contents will be described in detail through an embodiment according to the present invention.

2 is a circuit diagram illustrating a received signal attenuation circuit of a mobile communication terminal, and FIG. 3 is a graph illustrating amplification and attenuation characteristics of a field effect transistor in the received signal attenuation circuit of a mobile communication terminal. Table shows gain values according to input of field effect transistors.

As shown in FIG. 2, the first condenser 100 transmits an AC component from which a DC component is removed when a reception signal is input to a receiver of a mobile communication terminal (not shown). The capacitor 200 serves to remove noise of the attenuation control signal transmitted from the controller.

In addition, the first switching unit 300 is turned on when the attenuation control signal transmitted through the second condenser 200 is a high signal, and is turned off when a low signal, and the third capacitor 400 is the The second attenuation control signal serves to remove noise of another attenuation control signal, and the second switching unit 500 turns on when the attenuation control signal transmitted through the third capacitor 400 is a high signal and turns off when a low signal. do.

Subsequently, the voltage divider 600 determines a collector voltage of the first switch 300 and the second switch 500, and the fourth capacitor 700 controls the voltage divider 600. It plays a role of removing noise included in the attenuation value transmitted through.

Meanwhile, the field effect transistor 800 receives a received signal transmitted through the first capacitor 100 from a first gate pin, and receives a high or low signal of attenuation value transmitted through the fourth capacitor 700. The attenuation value is determined according to the difference between the two input signals received from the second gate pin and serves to attenuate the received signal of the mobile communication terminal accordingly.

In addition, the noise removing unit 900 removes noise included in the received signal attenuated or amplified by the field effect transistor 800, and the impedance matching unit 1000 performs the field effect transistor 800. This function prevents the voltage from being lost when the received signal transmitted from) is input to other circuits.

Meanwhile, the first, second, third, and fourth resistors 310, 320, 510, and 520 in the first and second switching units 300 and 500 may include the second capacitor 200 and the third capacitor ( It receives the received signal transmitted from 400 and distributes to the set voltage, the first transistor 330 receives the voltage divided through the first and second resistors (310, 320) and performs a switching role The second transistor 530 receives the voltages distributed through the third and fourth resistors 510 and 520, and performs the same switching role as the first transistor 330.

Hereinafter, the operation of the mobile communication terminal reception signal attenuation circuit configured as described above is as follows.

When a reception signal having a predetermined signal level or less is input to a reception unit of a mobile communication terminal (not shown), the first condenser 100 removes a DC component included in the reception signal and transmits the received signal as an AC component.

Then, the low signal is input so that the level of the received signal is not attenuated by the control signal transmitted from the control unit (not shown), and thus, the first and second transistors 310 and 510 in the first and second switching units 300 and 500. ) Is not turned on but is turned off and a preset reference voltage is input, and the third and fourth resistors 630 and 640 in the voltage divider 600 divide and transmit the reference voltage to the set voltage.

Then, the field effect transistor 800 receives and amplifies and transmits the set voltage transmitted from the voltage divider 700, and is amplified and transmitted from the field effect transistor 800 by the noise removing unit 900. When the received signal transmitted from the field effect transistor 800 in the impedance matching unit 1000 is input to the amplification unit and the automatic gain control unit mounted at the rear stage, the voltage is removed. This prevents the loss of.

At this time, when a received signal of a predetermined signal level or more is input to a mobile communication terminal (not shown), as shown in FIG. 4, the control unit transmits a signal corresponding to attenuation value corresponding to the level of the received signal as a high or low signal. If the transmitted attenuation value is, for example, a 12 dB level attenuation value, the control unit transmits a low signal to a transmission path that transmits a 12 dB attenuation value and a high signal to a transmission path that transmits a 24 dB attenuation value.

Then, the second capacitor 200 removes and transmits the noise included in the attenuation value transmitted as the high signal, and the third capacitor 400 removes and transmits the noise included in the attenuation value transmitted as the low signal. Let it be.

Subsequently, the first transistor 330 receives a high signal of attenuation value transmitted from the second capacitor 200 from the first and second resistors 310 and 320 inside the first switching unit 300. To be turned on, the first transistor 330 is turned on by the voltage transmitted through the first and second resistors 310 and 320, and the first in the first switching unit 300. The attenuation value transmitted from the transistor 310 and the preset reference voltage are attenuated by the first, third, and fourth resistors 610, 630, and 640 in the voltage divider 600 to a predetermined voltage. Down to distribute and send.

Then, the fourth capacitor 700 removes and transmits the noise included in the received signal attenuated by the voltage divider 600, and transmits the noise from the field effect transistor 800 to the fourth capacitor 700. Receives the received signal transmitted from and amplifies and transmits it.

Subsequently, the noise removing unit 900 removes noise included in the received signal transmitted from the field effect transistor 800, and the impedance matching unit 1000 receives the reception transmitted from the field effect transistor 800. This prevents the loss of voltage when the signal is sent to the amplifier and auto gain control unit (not shown) mounted at the rear end.

That is, by receiving the voltage of the received signal turned on and transmitted from the first switching unit 300 from the voltage divider 600, the magnitude of the voltage is divided by a plurality of resistance values in the voltage divider 600. The received signal voltage is amplified by the field effect transistor 800 having the characteristics as shown in FIG. 3 according to the transmitted value, so that when the level of the received signal is input above a certain level, the magnitude of the received signal You can send by adjusting.

In addition, when the level of the received signal is attenuated to 24 dB level, the above operation is performed, and the values of the second, third, and fourth resistors 610, 620, 630, and 64 in the voltage divider 600. As a result, the level of the received signal can be reduced.

As described above, the mobile communication terminal reception signal attenuation circuit according to the present invention uses a switching unit and a field effect transistor to amplify and attenuate the level of the reception signal, thereby constructing a reception signal attenuation circuit of the mobile communication terminal. The cost can be reduced, and the size and weight can be reduced.

Claims (3)

A first condenser for transmitting an AC component from which a DC component is removed when a reception signal is input to a receiving unit of the mobile communication terminal; A second capacitor for removing noise of the attenuation control signal transmitted from the control unit; A first switching unit turned on when the attenuation control signal transmitted through the second capacitor is a high signal, and turned off when a low signal; A third condenser for removing noise of another attenuation control signal of the controller; A second switching unit turned on when the attenuation control signal transmitted through the third capacitor is a high signal, and turned off when a low signal; A voltage divider configured to determine collector voltages of the first and second switches; A fourth capacitor for removing noise included in the attenuation value transmitted through the voltage divider; The received signal transmitted through the first capacitor is inputted from the first gate pin, and the high or low signal of the attenuation value transmitted through the fourth capacitor is inputted from the second gate pin and attenuated according to two input signal differences. A field effect transistor configured to determine and attenuate correspondingly the received signal of the mobile communication terminal; A noise removing unit for removing noise included in a received signal attenuated or amplified by the field effect transistor; And an impedance matching unit for preventing a voltage from being lost when the received signal transmitted from the field effect transistor is input to another circuit. The display device of claim 1, wherein the first switching unit comprises: first and second resistors configured to receive a received signal transmitted from a second capacitor and divide the received signal into a set voltage; And a first transistor configured to receive a voltage distributed through the first and second resistors and to perform an on / off switching function. The display device of claim 1, wherein the second switch comprises: third and fourth resistors configured to receive a received signal transmitted from a third capacitor and distribute the received signal to a set voltage; And a second transistor configured to receive an input voltage divided through the third and fourth resistors and perform an on / off switching function.