KR100692625B1 - Radio frequency module - Google Patents

Abstract

An RF(Radio Frequency) module is provided to remove the noise only irrespective of level properties of an inputted RF signal by comprising a noise eliminator for eliminating noise only of an IF(Intermediate Frequency), in a receiver, thus performance is improved in the receiver of the module. The first IF stage(21) consists of a mixer and an LO(Local Oscillator) for outputting a desired IF for an inputted RF signal. The second IF stage(22) consists of a mixer and an LO for outputting the second IF from the IF of the first IF stage(21). The third IF stage(23) consists of a mixer and an LO for outputting the third IF from the IF of the second IF stage(22). A noise eliminator(24) eliminates noise of the third IF on the third IF stage(23).

Description

RF module {RADIO FREQUENCY MODULE}

1 is a block diagram of a conventional RF module

2 is a block diagram of an RF module according to an embodiment of the present invention.

3 is a detailed block diagram of noise reduction of an RF module according to an exemplary embodiment of the present invention.

* Explanation of symbols for main parts of drawings *

21; First intermediate frequency 22; 2nd intermediate frequency

23; Third intermediate frequency break 24; Noise reduction means

LO1-LO3; First-third local oscillator MIX1-MIX3; mixer

The present invention relates to an RF module, and more particularly, to an RF module for reducing reception noise of an output terminal regardless of an input signal level to improve reception performance.

In general, an RF module is a component integrating a high frequency circuit in a wireless device, and the RF module is divided into two parts, the first of which is a generator and the second of which is a receiver.

The frequency generator generates frequency performance, purity, output level, etc. as main performances, and the receiver functions as nonlinear characteristic accuracy, signal resolution performance, minimum detect signal (MDS), and the like.

The most important factor in determining the performance of the receiver in the RF module based on the main performance is to minimize the minimum detection signal (MDS), which means the minimum power level (sensitivity) that can be received. Because it can.

However, all the components used in the receiver are designed in consideration of noise figure (NF), gain, loss characteristics, etc., wherein gain, loss, noise figure (NF) according to the characteristics of each component. The decision is made that the noise figure of the component selection and design has a low value and the gain and loss are equal to or higher than that.

That is, when the input signal is finally output, the size of the output signal is designed to be larger than the input. In this design, the noise figure (NF) value is always increasing.

F = F1 + (F2-1) / G1 + (F3-1) / G2 + (F4-1) / G3 + ....

F = F1 + SUM [{F (i + 1) -1} / Product {G) i}] NF = 10 * log 10 (F)

Where i is the order of connections from 1,2,3 ...

F is the calculated value of noise figure of each part,

G is an arithmetic value of the gain or loss value of each component.

The F value of the first stage determines the most important effect on the noise figure (NF) performance of the receiver.

Thus, as shown in FIG. 1, the receiver comprises three stages of the local oscillator LO1-LO3 and the mixer MIX1-MIX3 in order to obtain a desired intermediate frequency IF for the high frequency signal RF input. In order to minimize the minimum detection signal (MDS) at the front end of the receiver, a low noise amplifier (LNA) was configured to reduce the noise figure (NF).

When the noise index (NF) value is reduced, the total minimum detection signal (MDS) value of the receiver can be reduced, because the performance of the receiver can be improved.

MDS = -174 dBm / Hz + NF + 10 * log10 (BW)

Where -174 dBm / Hz; Noise level (kTB) at 1Hz bandwidth at room temperature

k; Boltzmann constant, T; Absolute temperature (273 + ° C.), B; Final processing band

However, when using the low noise amplifier (LNA), a phenomenon in which a large input signal cannot be processed due to the limitation of the linear response region of the amplifier occurs, that is, the maximum input level is limited by the gain of the amplifier.

Therefore, the noise level of the entire receiver is reduced, but the maximum signal level that can be processed by the receiver occurs, which causes a problem of degrading the performance of the receiver.

An object of the present invention is to improve the performance of the receiver by removing the noise only irrespective of the input level characteristics by providing a noise removing means in the receiver of the RF module.

It is another object of the present invention to facilitate signal processing by connecting a noise removing means for removing only noise to the end of the receiver.

In order to realize the above object, the present invention provides a first intermediate frequency circuit comprising a local oscillator and a mixer for outputting a desired intermediate frequency with respect to an input high frequency signal; A second intermediate frequency band comprising a local oscillator and a mixer for outputting a second intermediate frequency from the intermediate frequency of the first intermediate frequency band; A third intermediate frequency frequency band comprising a local oscillator and a mixer for outputting a third incremental frequency from an intermediate frequency of the second frequency frequency band; And a noise removing means for removing noise of the third intermediate frequency at the third intermediate frequency edge.

The noise canceling means includes: a divider for dividing a signal output from the third intermediate frequency edge; An amplifier for compensating for the gain of the signal divided into the divider; A summer for adding the signal whose gain is compensated in the amplifier and outputting the sum; An output divider for dividing and outputting the summed signal from the adder; An amplifier for compensating for the gain divided by the output divider; A mixer for mixing the gain compensated signal in the amplifier and the signal divided in the divider and outputting only a noise signal; A low pass filter for removing leakage noise from the noise signal output from the mixer; And a phase shifter for shifting the phase of the signal filtered by the low pass filter.

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

Figure 2 is a block diagram of the RF module according to an embodiment of the present invention, Figure 3 is a detailed block diagram of the noise module of the RF module according to an embodiment of the present invention, the present invention is a first intermediate frequency 21 And a second intermediate frequency edge 22, a third intermediate frequency edge 23, and a noise removing means 24.

The first intermediate frequency edge 21 includes a first local oscillator LO1 for outputting a predetermined local oscillation frequency; The first mixer MIX1 outputs the intermediate frequency signal IF1 by mixing the local oscillation frequency output from the first local oscillator LO1 and the input high frequency signal.

The second intermediate frequency terminal 22 mixes the intermediate frequency IF1 output from the first intermediate frequency terminal 21 with the local oscillation frequency of the second local oscillator LO2 that outputs a predetermined local oscillation frequency. It consists of the 2nd mixer MIX2 which outputs the intermediate frequency signal IF2.

The third intermediate frequency terminal 23 mixes the second intermediate frequency of the second intermediate frequency terminal 22 with the local oscillation frequency of the third local oscillator LO3 for outputting a predetermined local oscillation frequency. The third mixer MIX3 outputs IF3.

The noise removing means 24 is configured at the output end of the third mixer MIX3 to remove only the noise of the intermediate frequency signal IF3 output from the third intermediate frequency terminal 23.

The noise canceling means (24) comprises: a divider (B) output from the third intermediate frequency terminal (23) to divide the third intermediate frequency signal; An amplifier (C) (D) for compensating for the gain of the signal divided in the divider (B); A summer (I) for summing and outputting a signal whose gain is compensated in the amplifier (D); An output divider (F) for dividing and outputting the signal summed by the summer (I); An amplifier (E) for compensating for the gain divided by the output divider (F); A mixer (G) for outputting only noise by mixing the gain-compensated signal with the amplifier (E) and the divider (B) and the gain-compensated signal with the amplifier (C); A low pass filter (H) for removing leakage noise with respect to the noise signal output from the mixer (G); Phase shifter (J) for shifting the phase of the noise filtered by the low pass filter (H).

According to the present invention configured as described above, when the high frequency signal RF is inputted, the first intermediate frequency terminal 21 outputs the high frequency signal RF from the first local oscillator LO1 and a mixer. Mixing through the MIX1 outputs the intermediate frequency IF1 and inputs the output intermediate frequency IF1 to the second intermediate frequency terminal 22.

In the second intermediate frequency terminal 22, the intermediate frequency signal IF2 is mixed with the predetermined local oscillation frequency output from the second local oscillator LO2 through the mixer MIX2, and then the intermediate frequency signal IF2 is mixed. The output is input to the third intermediate frequency terminal 23.

In the third intermediate frequency terminal 23, the input intermediate frequency IF2 is mixed with the predetermined local oscillation frequency output from the third local oscillator LO3 through the mixer MIX3 and then the intermediate frequency signal IF3. Is outputted to the noise removing means 24, and the noise removing means 24 removes and outputs only the noise with respect to the intermediate frequency signal IF3 input from the third intermediate frequency terminal 23.

Therefore, if the noise removal process of the noise removing means 24 is developed in a formula,

Input signal (V1) = A * cos (wt + θ) + v noise1

Output signal (V4 ') = D * V1-v noise

             = D * (A * cos (wt + θ) + v noise1)-v noise

             = D * A * cos (wt + θ) + D * v noise1-v noise

            * D * v noise1> D * v noise1-v noise

            The noise signal level is reduced by the amount of v noise.

V1 = A * cos (wt + θ) + v noise1, V4 = D * V1

V2 = B * V1, V3 = C * V2 + v noise2, V5 = F * V4,

V6 = E * V5 + v noise3, V7 = G * (V3-V5), V8 = J * V7 (phase shifted)

Carrier signal input from V7, the signal output after passing through the mixer is limited in the low pass filter (H) to DC and noise signals.

V4 = D * (A * cos (wt + θ) + v noise1)

V8 = J * V7 = J * G * (V3-V5) = J * G * {(C * V2 + v noise2)-F * V4}

   = J * G * {(C * B * V1 + v noise2)-F * D * V1}

   = J * G * ((C * B * (A * cos (wt + θ) + v noise1) + v noise2)

     F * D * (A * cos (wt + θ) + v noise1)}

   = J * G * A * (C * B-F * D) * cos (wt + θ) + J * G * (C * B-F * D)

     * v noise1 + J * G * v noise2

   v noise = J * G * (C * B-F * D) * v noise1 + J * G * v noise2

When passing through the low pass filter (H), only v noise is output.

Final formula = V4-V8 = D * A * cos (wt + θ) + D * v noise1-v noise

As can be seen from the above equation, only the noise component is removed without damaging the level of the signal output from the main path.

In addition, a phase shifter J having a phase change at the final stage of the low pass filter H generates a phase change element, thereby removing noise components.

As described above, the present invention includes a noise removing means for removing only the noise of the intermediate frequency to the receiving portion of the RF module that outputs the desired intermediate frequency through the multi-stage intermediate frequency to the input high frequency signal. Since only noise is removed regardless of the level characteristic, the receiver of the RF module provides an effect of improving performance and facilitating signal processing.

Claims (2)

A first intermediate frequency terminal comprising a local oscillator and a mixer for outputting a desired intermediate frequency with respect to an input high frequency signal; A second intermediate frequency band comprising a local oscillator and a mixer for outputting a second intermediate frequency from the intermediate frequency of the first intermediate frequency band; A third intermediate frequency frequency band comprising a local oscillator and a mixer for outputting a third incremental frequency from an intermediate frequency of the second frequency frequency band; And the third intermediate frequency edge includes noise removing means for removing noise of a third intermediate frequency. 2. The apparatus of claim 1, wherein the noise removing means comprises: a divider for dividing a signal output from the third intermediate frequency edge; An amplifier for compensating for the gain of the signal divided into the divider; A summer for adding the signal whose gain is compensated in the amplifier and outputting the sum; An output divider for dividing and outputting the summed signal from the adder; An amplifier for compensating for the gain divided by the output divider; A mixer for mixing the gain compensated signal in the amplifier and the signal divided in the divider and outputting only a noise signal; A low pass filter for removing leakage noise from the noise signal output from the mixer; And a phase shifter for shifting the phase of the signal filtered by the low pass filter.

Images