KR100650331B1 - Signal response circuit with improved gain ratio and frequency mixer including the same - Google Patents

Abstract

A signal response circuit having an improved gain ratio and a frequency mixer including the same are disclosed. The signal response circuit of the present invention includes response means for controlling an amount of current flowing between a first response end and a first output end, and between a second response end and a second output end, and a change in voltage level at the first and second response ends. And said negative conductance means being driven to accelerate in the same direction. According to the signal response circuit of the present invention, an output signal having a high amplification factor with respect to the input signal is generated. In addition, according to the frequency mixer of the present invention, in response to a wireless communication signal, a wireless communication response unit for generating a response communication signal and the frequency of the local communication signal by combining the frequency of the response communication signal to the modulated output signal And a switching unit including first and second signal response circuits. In this case, the first and second signal response circuits are implemented by the signal response circuit of the present invention. In the frequency mixer of the present invention, as compared with the conventional frequency mixer, the switching characteristic of the frequency mixer with respect to the amplitude of the local communication signal is closer to an ideal situation. As a result, the modulated output signal can effectively synthesize a frequency of the wireless communication signal and the local communication signal.

Description

Signal Responding Circuit with improved gain And Frequency Mixer having the same}

In order to more fully understand the drawings used in the detailed description of the invention, a brief description of each drawing is provided.

1 is a view showing a conventional signal response circuit.

2 is a view showing a conventional frequency mixer.

3 is a circuit diagram illustrating a signal response circuit according to an embodiment of the present invention.

4 is a view for explaining the variation of the amplitude of the output signal according to the input signal in the signal response circuit of the prior art and the present invention.

5 is a frequency mixer according to an embodiment of the present invention, and employs the signal response circuit of FIG.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to electronic circuits, and more particularly, to a frequency mixer for synthesizing frequencies of wireless communication signals and local communication signals.

Recently, radio frequency (RF) communication systems have been provided for various services such as various types of communication, radiotelephony, satellite broadcasting, CATV, and the like. Such an RF communication system includes a frequency mixer that synthesizes a high frequency local communication signal into a low frequency wireless communication signal and generates a modulated output signal. At this time, the frequency mixer includes a signal response circuit for generating an output signal in response to the received input signal.

1 is a view showing a conventional signal response circuit. The signal response circuit of FIG. 1 generates an output signal VOUT in response to the input signal IN. In FIG. 1, the voltage levels of the input signal IN and the output signal VOUT are represented by the difference between the voltage levels of their positive and negative components. And, in the present specification, each signal is represented only by IN, VOUT, etc., each positive component is indicated by adding (+) to the reference numeral and negative component by adding (-) to the reference numeral.

By the way, according to the conventional signal response circuit as shown in FIG. do. That is, the amplitude VOUTh1 of the output signal VOUT and the amplitude INh of the input signal IN have the same relationship as Equation (1).

(Equation 1)

VOUTh1 = α · gm · INh, where α is proportional constant

However, gm has a certain limit due to the physical characteristics of the transistor. Therefore, according to the conventional signal response circuit, the amplification rate of the output signal VOUT with respect to the input signal IN has a limit.

2 shows a conventional frequency mixer, which uses the signal response circuit of FIG. In FIG. 2, the voltage levels of the radio communication signal RF, the response communication signal RS, the local communication signal LO, and the modulation output signal IF are respectively positive and negative components. This is indicated by the difference in voltage levels. And, in the present specification, each signal is represented only by RF, RS, IF, LO, etc., each positive component is indicated by adding (+) to the reference numeral and negative component by adding (-) to the reference numeral.

In the frequency mixer of FIG. 2, the radio mixer includes a radio communication response unit 10 and a switching unit 20. The radio communication response unit 10 generates a response communication signal RS in response to the radio communication signal RF. The response communication signal RS swings at the same frequency as the radio communication signal RF. The first switching means 21 and the second switching means 23 of the switching unit 20, through the respective source terminal NS1, NS2, the positive component (RS +) and the negative of the response communication signal Receive component RS-. In addition, the transistors 21a, 21b, 23a, and 23b of the first and second switching means 21 and 23 may have conductances according to the positive component LO + and the negative component LO− of the local communication signal. Thus, the positive component RS + and the negative component RS- of the response communication signal are transmitted to generate a modulated output signal IF. Therefore, in order for the modulation output signal IF generated by the switching unit 20 to effectively synthesize the frequencies of the radio communication signal RF and the local communication signal LO, the modulation output signal IF is generated. It is required to have a high amplification rate for the local communication signal LO.

By the way, in the conventional frequency mixer as shown in Fig. 2, the signal response circuit as shown in Fig. 1 is incorporated in the switching section. Therefore, in the conventional frequency mixer, there arises a problem that the amplification factor of the modulated output signal IF has a limit point for the local communication signal LO.

Accordingly, an object of the present invention is to solve the problems of the prior art, to provide a signal response circuit for generating an output signal having a high amplification rate for the input signal and a frequency mixer including the same.

One aspect of the present invention for achieving the above technical problem relates to a signal response circuit for generating an output signal in response to a received input signal. Here, the voltage levels of the input signal and the output signal are voltage levels according to differences between respective positive and negative components. The signal response circuit of the present invention comprises a predetermined source end; Responsive to a positive component and a negative component of the input signal, respectively, between a predetermined first response stage and a first output stage that generates a positive component of the output signal, and a predetermined second response stage and the Response means for controlling an amount of current flowing between second output stages for generating a negative component of the output signal; And negative conductance means formed between a predetermined source terminal and the first and second response terminals, wherein the negative conductance is driven to accelerate in the same direction with respect to a change in voltage level in the first and second response terminals. Means.

Another aspect of the present invention for achieving the above technical problem relates to a frequency mixer for generating a modulated output signal by combining a predetermined wireless communication signal and a predetermined local communication signal. Here, the voltage levels of the wireless communication signal, the local communication signal, and the modulation output signal are voltage levels according to differences between respective positive and negative components. The frequency mixer of the present invention is a wireless communication response unit which generates a predetermined response communication signal by differentially responding to a positive component and a negative component of the wireless communication signal. The voltage level is the wireless communication response unit which is a voltage level according to a difference between its positive component and a negative component; And receiving a positive component and a negative component of the response communication signal to respective source terminals, and generating the modulated output signal by combining the frequency of the local communication signal with the frequency of the response communication signal. And a switching unit including first and second signal response circuits. And at least one of the first and second signal response circuits responds to a positive component and a negative component of the local communication signal, respectively, to determine a predetermined first response stage and the modulation output signal. Response means for controlling the amount of current flowing between a first output stage for generating a positive component and between a predetermined second response stage and a second output terminal for generating a negative component of the modulated output signal; And negative conductance means formed between a predetermined source terminal and the first and second response terminals, wherein the negative conductance means is driven to accelerate in the same direction with respect to a change in the voltage level at the first and second response terminals. It is provided.

In order to fully understand the present invention, the operational advantages of the present invention, and the objects achieved by the practice of the present invention, reference should be made to the accompanying drawings which illustrate preferred embodiments of the present invention and the contents described in the accompanying drawings.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. For each figure, like reference numerals denote like elements.

3 is a circuit diagram illustrating a signal response circuit according to an embodiment of the present invention. The signal response circuit of FIG. 3 generates an output signal VOUT in response to the received input signal IN. In this case, in FIG. 3, the voltage levels of the input signal IN and the output signal VOUT are represented by the difference between the voltage levels of the positive and negative components. And, in the present specification, each signal is represented only by IN, VOUT, etc., each positive component is indicated by adding (+) to the reference numeral and negative component by adding (-) to the reference numeral.

Referring to FIG. 3, the signal response circuit of the present invention includes a predetermined source terminal NS, a response means 30, and a negative conductance means 40. In this case, a source signal XSOR swinging at a predetermined amplitude may be applied to the source terminal NS. In addition, a source voltage such as ground voltage VSS may be applied to the source terminal NS.

In addition, the response means 30 specifically includes first and second response transistors 31 and 33. The first response transistor 31 is gated by the positive component IN + of the input signal, and one source / drain terminal is connected to the first output terminal NOUT +. The first response transistor 31 controls the amount of current flowing between the first response terminal NRa and the first output terminal NOUTa according to the positive component IN + of the input signal. The first response transistor 31 provides a positive component VOUT + of the output signal through the first output terminal NOUTa.

The second response transistor 33 is gated by the negative component IN− of the input signal, and one source / drain terminal is connected to the second output terminal NOUTb. The second response transistor 33 controls the amount of current flowing between the second response terminal NRb and the second output terminal NOUTb according to the negative component IN− of the input signal. The second response transistor 33 provides the negative component VOUT− of the output signal through the second output terminal NOUTb.

In a preferred embodiment, the first and second response transistors 31 and 33 are NMOS transistors.

The negative conductance means 40 is formed between a predetermined source terminal NS and the first and second response terminals NRa and NRb. The negative conductance means 40 is driven to float in the same direction against changes in voltage levels at the first and second response stages NRa and NRb.

The negative conductance means 40 more particularly comprises a first negative transistor 41 and a second negative transistor 43. The first negative transistor 41 is connected between the source terminal NS and the first response terminal NRa and is gated by the second response terminal NRb. In addition, the second negative transistor 43 is connected between the source terminal NS and the second response terminal NRb and is gated by the first response terminal NRa.

That is, the first negative transistor 41 and the second negative transistor 43 are cross-coupled with each other. Therefore, when the voltage level of the first response terminal NRa increases, the second negative transistor 43 serves to lower the voltage level of the second response terminal NRb. As a result, the conductance of the first negative transistor 41 decreases, and the voltage level of the first response terminal NRa further increases. When the voltage level of the first response terminal NRa falls, the voltage level of the second response terminal NRb increases, and as a result, the voltage level of the first response terminal NRa falls further. do.

Accordingly, the negative conductance means 40 is driven to further accelerate in the same direction with respect to the change in the voltage level of the first response stage NRa.

Further, by the same principle, the negative conductance means 40 is driven to further accelerate in the same direction with respect to the change in the voltage level of the second response stage NRb.

That is, it can be understood that the resistance value RL of the negative conductance means 40 has a negative value. For reference, in the present embodiment, when the resistance value or the conductance is positive (+), it acts in the direction of preventing the change with respect to the change in the input voltage level.

According to a preferred embodiment, the first and second negative transistors 41 and 43 are NMOS transistors.

In the present embodiment, the conductance of the first and second response transistors 31 and 33 included in the response means 30 is gm, and the resistance value of the negative conductance means 40 is -RL. Then, the conductance Gm of the signal response circuit of the present invention is as shown in Equation (2).

(Equation 2)

Gm = βgm / (1-gmRL)

In the present invention, the amplitude VOUTh2 of the output signal VOUT and the amplitude INh of the input signal IN have a relationship as shown in Equation (3).

(Equation 3)

VOUTh2 = α · Gm · INh (where α is proportional constant)

    = alpha beta INh gm / (1-gm RL)

That is, when the RL is designed to be close to −1 / gm, the amplitude VOUTh2 of the output signal VOUT is significantly increased, as shown in FIG. Theoretically, if the RL is equal to -1 / gm, the VOUTh2 becomes infinity. In Fig. 4, the amplitudes of the input signal IN and the output signal VOUT are shown on a log scale.

5 is a circuit diagram illustrating a frequency mixer according to an embodiment of the present invention, and employs the signal response circuit of FIG. In FIG. 5, as in FIG. 2, the voltage levels of the radio communication signal RF, the response communication signal RS, the local communication signal LO, and the modulation output signal IF are positive components. And the difference in voltage levels of negative components. And, in the present specification, each signal is represented only by RF, RS, IF, LO, etc., each positive component is indicated by adding (+) to the reference numeral and negative component by adding (-) to the reference numeral.

The frequency mixer of the present invention shown in FIG. 5 synthesizes a radio communication signal RF and a local communication signal LO. In this case, the wireless communication signal RF is relatively high frequency, and the local communication signal LO is relatively low frequency. The radio communication signal RF and the local communication signal LO generally have a frequency of about several G Hz.

The frequency mixer of the present invention includes a wireless communication response unit 100 and a switching unit 200. The wireless communication response unit 100 generates a response communication signal RS in response to the wireless communication signal RF in a differential manner. The switching unit 200 supplies the positive component RS + and the negative component RS− of the response communication signal to the first source terminal NSa and the second signal of the first signal response circuit 210, respectively. The signal is received by the second source terminal NSb of the response circuit 230. The switching unit 200 generates the modulation output signal IF by combining the local communication signal LO with the response communication signal RS. That is, the frequency of the modulation output signal IF has a frequency obtained by combining the frequencies of the response communication signal RS and the local communication signal LO.

The first signal response circuit 210 and the second signal response circuit 230 are implemented in the form of a signal response circuit as shown in FIG. 3. In this case, the local communication signal LO in FIG. 5 corresponds to the input signal IN in FIG. 3, and the modulation output signal IF in FIG. 5 corresponds to the input signal VOUT in FIG. 3.

Therefore, by the first signal response circuit 210 and the second signal response circuit 230, the amplification ratio of the amplitude of the modulation output signal IF to the amplitude of the local communication signal LO is significantly improved. Can be as described with reference to FIG. 3.

In conclusion, in the frequency mixer of the present invention, as compared with the conventional frequency mixer, the amplification ratio of the amplitude of the modulated output signal IF to the amplitude of the local communication signal LO increases at a significant rate. As a result, the modulated output signal IF may effectively synthesize the frequencies of the wireless communication signal RF and the local communication signal LO.

In other words, according to the frequency mixer of the present invention, even if a local communication signal LO having a rather small amplitude is received, the modulated output signal can obtain the same amplitude as in the prior art.

The signal response circuit of the present invention as described above includes response means for controlling the amount of current flowing between the first response end and the first output end, and between the second response end and the second output end, and the voltage levels at the first and second response ends. With respect to the change of, the negative conductance means is driven to accelerate in the same direction.

According to the signal response circuit of the present invention as described above, an output signal having a high amplification factor with respect to the input signal is generated.

In addition, according to the frequency mixer of the present invention, in response to a wireless communication signal, a wireless communication response unit for generating a response communication signal and the frequency of the local communication signal by combining the frequency of the response communication signal to the modulated output signal And a switching unit including first and second signal response circuits. In this case, the first and second signal response circuits are implemented by the signal response circuit of the present invention.

In the frequency mixer of the present invention as described above, as compared with the conventional frequency mixer, the amplification ratio of the amplitude of the modulated output signal IF to the amplitude of the local communication signal LO increases at a significant rate. As a result, the modulated output signal IF may effectively synthesize the frequencies of the wireless communication signal RF and the local communication signal LO.

In other words, according to the frequency mixer of the present invention, even if a local communication signal LO having a rather small amplitude is received, the modulated output signal can obtain the same amplitude as in the prior art.

Although the present invention has been described with reference to one embodiment shown in the drawings, this is merely exemplary, and those skilled in the art will understand that various modifications and equivalent other embodiments are possible therefrom.

For example, in this specification, an embodiment is shown and described in which both the first and second signal response circuits in the frequency mixer of the present invention are implemented with the signal response circuit of the present invention. However, the technical idea of the present invention can be realized to a considerable extent even by an embodiment in which at least one of the first and second signal response circuits is implemented as the signal response circuit of the present invention.

Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

Claims (6)

A frequency mixer for generating a modulated output signal by combining a predetermined wireless communication signal and a predetermined local communication signal, wherein voltage levels of the wireless communication signal, the local communication signal, and the modulated output signal are positive components of each other. In the frequency mixer which is the voltage level according to the difference between the negative and negative components, A wireless communication response unit for generating a predetermined response communication signal in response to a positive component and a negative component of the wireless communication signal in a differential manner, wherein the voltage level of the response communication signal is positive. The wireless communication response unit which is a voltage level according to a difference between a positive component and a negative component; And Receiving a positive component and a negative component of the response communication signal to respective source terminals, wherein the modulation output signal is generated by combining the frequency of the local communication signal with the frequency of the response communication signal. A switching unit including first and second signal response circuits, At least one of the first and second signal response circuits In response to a positive component and a negative component of the local communication signal, respectively, between a predetermined first response stage and a first output stage that generates a positive component of the modulated output signal and a predetermined second response. Response means for controlling an amount of current flowing between a stage and a second output stage for generating a negative component of the modulated output signal; And Negative conductance means formed between a predetermined source terminal and the first and second response terminals, wherein the negative conductance is driven to accelerate in the same direction with respect to a change in the voltage level at the first and second response terminals. And a means for providing a frequency mixer. The method of claim 1, wherein the response means Controlling the amount of current flowing between the first response terminal and the first output terminal and between the second response terminal and the second output terminal in response to a positive component and a negative component of the local communication signal, respectively. And a first and second response transistor. The method of claim 2, wherein the negative conductance means A first negative transistor connected between the source terminal and the first response terminal and gated by the second response terminal; And And a second negative transistor coupled between the source terminal and the second response terminal and gated by the first response terminal. The method of claim 3, wherein the first response transistor, the second response transistor, the first negative transistor, and the second negative transistor are each A frequency mixer, characterized in that implemented by the NMOS transistor. The method of claim 1, wherein the wireless communication signal And a frequency mixer higher than the frequency of the local communication signal. A signal response circuit for generating an output signal in response to a received input signal, wherein the voltage level of the input signal and the output signal is a voltage level according to a difference between a positive component and a negative component In the above signal response circuit, A predetermined source end; Responsive to a positive component and a negative component of the input signal, respectively, between a predetermined first response stage and a first output stage that generates a positive component of the output signal, and a predetermined second response stage and the Response means for controlling an amount of current flowing between second output stages for generating a negative component of the output signal; And A negative conductance means formed between a predetermined source terminal and the first and second response terminals, the negative conductance means being driven to accelerate in the same direction with respect to a change in the voltage level at the first and second response terminals. Signal response circuit characterized in that provided.

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