KR20040046184A - Signal recieving device - Google Patents

Abstract

PURPOSE: A signal receiver is provided to prevent receive sensitivity of a received signal and signal-to-noise ratio from being decreased caused by an oscillating frequency and a multiplied frequency of the oscillating frequency. CONSTITUTION: A signal receiver includes a microcomputer(30), an oscillator(40), and a frequency shifter(50). The microcomputer is operated in response to a predetermined operating clock signal and receives a signal with a predetermined frequency from an external device. The oscillator generates an oscillating frequency in response to the operating clock signal of the microcomputer. The frequency shifter shifts the oscillating frequency to prevent the frequency of the signal received by the microcomputer and the oscillating frequency from interfering with each other. The frequency shifter includes a power supply terminal(51), the first transistor(Q1) whose emitter is connected to the power supply terminal, the second and third transistors(Q2,Q3) whose bases are connected to the collector of the first transistor through resistors(R1,R2), respectively, and the first and second condensers(C5,C6) respectively connected between the second and third transistors and clock terminals(31,32) of the microcomputer.

Description

Signal Receiving Device

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a signal receiving apparatus, and in particular, a reception sensitivity and a signal-to-noise ratio due to mutual interference between a frequency of a signal received from the outside and an oscillation frequency according to an internal operating clock for processing the received signal are increased. The present invention relates to a signal receiving apparatus in which deterioration is prevented.

As shown in FIG. 1, the signal receiving apparatus according to the related art has a set operating clock and receives a signal having a set frequency from the outside, and an oscillation frequency according to the operating clock of the microcomputer 10 It is configured to include the oscillator 20 is generated and output.

Here, the microcomputer 10 further includes a plurality of clock terminals 11 and 12 to which the oscillation frequency output from the oscillator 20 is input, and a ground terminal 13 connected to the ground.

On the other hand, the oscillator 20 is composed of an oscillator 21 and a plurality of capacitors (C1, C2) oscillating in accordance with the operation clock, the oscillation frequency is the capacitor (C1, together with the oscillation of the oscillator 21) It depends on the capacitor capacity generated by C2).

In addition, the oscillator 20 is connected to a power supply terminal 2 that supplies power to the oscillator 21 and allows the capacities of the capacitors C1 and C2 to be generated.

The signal receiving apparatus according to the related art is a reception sensitivity of the received signal by the oscillation frequency and the multiplying frequency when a portion where the frequency of the received signal and the multiplication frequency of the oscillation frequency and the oscillation frequency overlaps. And a signal-to-noise (S / N) ratio is lowered.

The present invention has been made to solve the above problems of the prior art, an object thereof is to shift the oscillation frequency to prevent the frequency and the oscillation frequency and the multiplication frequency of the signal received from the outside overlapping to prevent the The present invention provides a signal receiving apparatus capable of preventing a decrease in reception sensitivity and signal-to-noise (S / N) ratio of the received signal due to an oscillation frequency and a multiplication frequency thereof.

1 is a circuit diagram showing the configuration of a signal receiving apparatus according to the prior art;

2 is a circuit diagram showing the configuration of a signal receiving apparatus according to the present invention.

<Explanation of symbols on main parts of the drawings>

30: microcomputer 31, 32: clock terminal

33: ground terminal 34: control terminal

40: oscillator 41: oscillator

50: frequency shift unit 51: power supply terminal

Q1: first transistor Q2: second transistor

Q3: third transistor C5: first capacitor

C6: second capacitor

The signal receiving apparatus according to the present invention for solving the above problems is a microcomputer that operates according to a set operating clock and receives a signal of a set frequency from the outside, and an oscillator and capacitor generating and outputting an oscillating frequency according to the operating clock of the microcomputer. And an oscillation unit consisting of an oscillation unit and a frequency shifting unit for shifting the oscillation frequency so as not to overlap the frequency of the reception signal so as to prevent mutual interference between the oscillation frequency and the frequency of the reception signal.

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

As shown in FIG. 2, the apparatus for receiving a signal according to the present invention operates according to a set operating clock and receives a signal having a frequency set from the outside, and an oscillation frequency according to the operating clock of the microcomputer 30. And an oscillator 40 for generating and outputting the oscillator 40, and a frequency shifter 50 for shifting the oscillation frequency to prevent mutual interference between the oscillation frequency and the frequency of the received signal.

Here, the microcomputer 30 operates the clock terminals 31 and 32 to which the oscillation frequency output from the oscillator 40 is input, the ground terminal 33 connected to the ground, and the frequency shift unit 50. The control terminal 34 further includes a control terminal 34. In particular, the control terminal 34 determines whether the frequency shift unit 50 is operated, and the frequency shift unit 50 is oscillated from the oscillator 40. Allow the frequency to shift.

The oscillator 40 includes an oscillator 41 oscillating according to the operation clock and a plurality of capacitors C3 and C4 to generate and output an oscillation frequency according to the operation clock. The oscillation frequency is the oscillator 41. ) And the capacity by the capacitors C3 and C4.

The frequency shift unit 50 includes a power supply terminal 51 to which power is supplied from the outside, a first transistor Q1 to which an emitter is connected to the power supply terminal 51, and the first transistor. Second and third transistors Q2 and Q3 to which a base is connected through a collector of Q1 and resistors R1 and R2, respectively, and the second and third transistors Q2 and Q3. And first and second capacitors C5 and C6 connected between the clock terminals 31 and 32, respectively.

In addition, the base of the first transistor Q1 is connected to the control terminal 34 through a resistor R3, and is turned on / off according to a signal generated from the control terminal 34. When Q1) is turned on, the second and third transistors Q2 and Q3 are turned on and thus the capacitances of the first and second capacitors C5 and C6 and the capacitors C3 and C4 of the oscillator 40. Due to the capacitance of the total capacitor capacity is changed, which causes the oscillation frequency output from the oscillator 40 is shifted.

The operation of the signal receiving apparatus according to the present invention configured as described above is as follows.

In the operation of the signal receiving apparatus according to the present invention, first, the microcomputer 30 receives a signal having a frequency set from the outside according to an operation clock corresponding to the oscillation frequency output from the oscillator 40.

In this case, when the frequency of the received signal, the oscillation frequency and the multiplier frequency of the oscillation frequency overlap and mutual interference occurs, the reception sensitivity of the received signal is impaired, so that the microcomputer 30 is controlled through the control terminal 34. One transistor Q1 is turned on.

Here, the frequency and the oscillation frequency of the received signal are pre-stored in the microcomputer 30, and the portion where the microcomputer 30 overlaps or approaches by comparing the oscillation frequency and its multiplied frequency with the frequency of the received signal occurs. In this case, a signal is generated through the control terminal 34.

As the first transistor Q1 is turned on, a collector current according to the power supply terminal 51 is generated in the first transistor Q1, and the generated collector current is generated in the second and third transistors Q2 and Q3. Is applied to the base.

Capacitance by the first and second capacitors C5 and C6 when the second and third transistors Q2 and Q3 are turned on due to currents applied to the bases of the second and third transistors Q2 and Q3. Is generated.

At this time, the total capacitor capacity is changed by the capacitors C3 and C4 of the oscillator 40 and the capacities of the first and second capacitors C5 and C6, and the oscillation output from the oscillator 40 accordingly. The frequency is shifted.

As a result, the signal receiving apparatus according to the present invention prevents mutual interference from occurring because the frequency and oscillation frequency of a signal received from the outside overlap or approach each other, thereby improving the reception sensitivity and signal-to-noise ratio of the received signal. It can be.

The signal receiving apparatus according to the present invention configured as described above operates according to a set operation clock and receives a signal having a frequency set from the outside, an oscillator generating and outputting an oscillation frequency according to the operation clock of the microcomputer, and the oscillation. And a frequency shifter for shifting the oscillation frequency to prevent mutual interference between a frequency and a frequency of the received signal, so that the frequency of the signal received from the micom to the micom is output from the oscillator. And judging whether a portion overlapping or approaching the multiplication frequency is generated, and when the overlapping or approaching part occurs as a result, the oscillation frequency generated by changing the capacitor capacity generated by the oscillator through the frequency shifter is shifted. By In addition, there is an effect that the reception sensitivity and the signal-to-noise (S / N) ratio of the received signal can be improved by preventing mutual interference that may occur between the frequency of the received signal, the oscillation frequency, and the multiplication frequency in advance.

Claims (3)

An oscillation unit consisting of a microcomputer operating according to a set operating clock and receiving a signal having a set frequency from the outside, an oscillator and a capacitor generating an oscillating frequency according to the operating clock of the microcomputer, and mutual interference between the oscillating frequency and the frequency of the received signal And a frequency shifter for shifting the oscillation frequency so as to prevent the signal from overlapping with the frequency of the received signal. The method of claim 1, The frequency shift unit includes a power supply terminal to which power is supplied from an external source, a first transistor to which the power supply terminal and an emitter are connected, second and third transistors to which a base and a collector of the first transistor are connected, respectively, And first and second capacitors connected between the collectors of the second and third transistors and the microcomputer, respectively. The method of claim 2, The microcomputer further includes a control terminal connected to the base of the first transistor to turn on / off the first transistor, wherein when the first transistor is turned on, the second and third transistors are turned on and accordingly And a capacitance of the capacitor generated by the oscillator is changed by the capacitances of the generated first and second capacitors so that the oscillation frequency is shifted.