KR100662926B1 - Apparatus for detecting the state of a transmission signal level and a reception signal level - Google Patents

Abstract

The present invention provides a state detection apparatus of a transmit / receive signal level that detects a state of a signal level transmitted through a transmit / receive path so that the gain of the transmit / receive path can be adjusted to an optimal state in the transceiver. To this end, the apparatus according to the present invention, the signal strength detector 202 for detecting the strength of the signal of the stage prevailing in the front-receiving device, the threshold for converting the predetermined threshold value in digital form In the value converter 208, the converter 210 for converting the threshold value output from the threshold converter 208 to an analog signal having a constant level and outputs, the value output from the signal strength detector 202 and the converter 210 The comparator 204 for comparing the magnitudes of the output values and the signal output from the comparator 204 detect the state of the current level of the signal and provide them for consideration when adjusting the receiving path or the gain of the transmitting path. State detector 214. Therefore, the gain of the transmission path or the reception path of the corresponding transceiver can be adjusted to an optimal state.

Description

Transmitter and Signal Level Detection Device {APPARATUS FOR DETECTING THE STATE OF A TRANSMISSION SIGNAL LEVEL AND A RECEPTION SIGNAL LEVEL}

1 is a schematic block diagram of a transmission and reception matching block provided in a general RF transceiver;

2 is a block diagram of a state detection apparatus of a transmit / receive signal level according to the present invention;

3 is an operation waveform diagram of a state detection apparatus of a transmit / receive signal level shown in FIG.

4 is a detailed circuit diagram of the state detector shown in FIG.

FIG. 5 is a state transition diagram used in the state machine shown in FIG. 4,

FIG. 6 is a state diagram in which an existing intermodulation state detection process and a state detection amount of a corresponding signal level react according to a RISE or FALL threshold value shown in FIG. 5.

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

202: signal strength detector 204: comparator

206: threshold generator 208: threshold converter

210: D / A converter 211: Pulse width modulator (PWM)

212: low pass filter 214: state detector

401: chattering detection unit 405: state machine

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for detecting transmit / receive signal levels, and more particularly, to an apparatus for detecting transmit / receive levels that detects the state of transmit / receive signal levels so as to adjust an optimal transmit / receive gain.

In general, a transceiver is a device that receives and transmits a signal including, for example, a radio frequency (RF), an amplitude modulation (AM), a frequency modulation (FM), a phase modulation (PM), and the like through an antenna. These transceivers are provided with a transmission / reception matching block that can adjust the intensity of signals transmitted and received.

1 is a transmission / reception matching block included in an RF transceiver, including an antenna 102, a duplexer 104, a low noise amplifier 106 (hereinafter referred to as LNA) 106, and an RF (Radio) receiver. Frequency 108 (abbreviated as RF) amplifier 108 and IF (Intermediate Frequency (abbreviated IF) amplifier) 110, receiving side AGC (RX AGC) 112, transmitting side AGC (TX AGC) 116, transmission The side IF amplifier 118 and the power amplifier (hereinafter referred to as PA) 120, the LNA 106, the RX AGC 112, and TX so that the strength of the received signal and the strength of the transmitted signal can satisfy the set level. And a level detection and gain control unit 114 for controlling the gain amounts of the AGC 116 and the PA 120.

In the transmission and reception matching block configured as described above, the RF signal received through the antenna 102 and the duplexer 104 is leveled through the LNA 106, the RF amplifier 108, the IF amplifier 110, and the RX AGC 112. The detection and gain control unit 114 is transmitted. The level detection and gain control unit 114 detects the strength of the received signal by the signal transmitted from the RX AGC 112, and the LNA 106 so that the detected strength of the received signal satisfies the desired strength condition of the received signal. And control gain of RX AGC 112.

That is, at the initial stage of driving, the level detection and gain control unit 114 sets the LNA 106 to the bypass state so that the received RF signal passes through the LNA 106 as it is, and then sets the LNA 106 to the RX AGC 112. While controlling the strength of the received signal for the RF signal transmitted from the duplexer 104 while adjusting the gain amount, the LNA_RANGE value is determined when the strength of the signal transmitted from the RX AGC 112 does not satisfy the specified received signal strength. By setting the RF signal transmitted from the duplexer 104 to the high frequency amplification in the LNA (106). The LNA_RANGE value is set to a high value when the strength of the signal transmitted from the RX AGC 112 is less than the predetermined strength of the received signal, and set to a low value when the strength of the transmitted signal is greater than the strength of the received signal. .

The LNA 106 amplifies the RF signal transmitted from the duplexer 104 according to the gain amount determined by the LNA_RANGE value set as described above, and converts the amplified signal into the RF amplifier 108, the IF amplifier 110, and the RX AGC 112. ) Is transmitted to the level detection and gain control unit 114. At this time, when the detected intensity of the received signal does not satisfy the predetermined intensity of the received signal, the level detecting and gain adjusting unit 114 sets the LNA_GAIN value to further control the gain amount for the LNA 106. That is, when the detected intensity of the received signal is lower than the determined intensity of the received signal, the gain amount of the LNA 106 is set to be large, and when the detected received intensity is greater than the determined intensity of the received signal, the gain of the LNA 106 is set. Set the amount small.

As described above, in the transmission / reception matching block provided in the conventional RF transceiver, the gain amount of the reception path is adjusted by the strength of the reception signal detected by the signal output from the RX AGC 112, and thus the strengths of the detected reception signals are mutually different. In the case of the influence of an intermodulation (IM) signal, it is not possible to determine whether it is caused by the LNA 106 or the RX AGC 112, and thus it is not possible to adjust the correct reception gain.

Meanwhile, the strength of the transmission signal is variably adjusted by the PA_GAIN value for the PA 120 and the TX_AGC_ADJ value for the TX AGC 116 set by the level detection and gain control unit 114. The PA_GAIN value is a fixed value. Since the TX_AGC_ADJ is variably set, the strength of the transmission signal is controlled. At this time, the TX_AGC_ADJ value is determined by the strength of the transmission signal requested from the base station not shown.

As such, the strength of the existing transmission signal is controlled by setting the TX_AGC_ADJ value according to the strength of the transmission signal required by the base station (not shown), thereby verifying whether the actual transmission signal strength is transmitted to the desired transmission signal strength. I could not.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and provides an apparatus for detecting a state of a transmit / receive signal level implemented to detect a state of a transmit / receive signal level (or transmit / receive signal strength) in order to control an optimal transmit / receive gain. have.

Another object of the present invention is a state detection apparatus of a transmit / receive signal level implemented to detect a state of a transmit / receive signal level using characteristics of a dominant transmit / receive end (RF stage) in a transceiver. To provide.

In order to achieve the above objects, the apparatus for detecting a state of a transmit / receive signal level according to the present invention is connected to a receiving path and a transmitting path of a transmitting / receiving device that can adjust a gain of a signal, and a level of a signal transmitted through the receiving path and the transmitting path. An apparatus for detecting a state, comprising: a signal strength detector for detecting the strength of a signal at a stage where the influence of a front end prevails on each of a reception path and a transmission path; A threshold converter for converting a predetermined threshold value in digital form; A converter for converting a digital threshold value converted from the threshold converter into an analog signal having a predetermined level and outputting the analog signal; A comparator for comparing the magnitude between the signal strength value detected by the signal strength detector and the value output from the converter; And a state detector for detecting a state of a current level of a signal corresponding to the intensity detected by the signal strength detector according to the signal output from the comparator.

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

2 is a functional block diagram of a state detection apparatus of a transmit / receive signal level according to the present invention, which generates a signal strength detector 202 for detecting the strength of a signal to be detected and a threshold value corresponding to a detection reference value of a signal to be detected. The threshold value generator 206, the threshold value converter 208 for converting the generated threshold value into a digital form so as to obtain a constant DC form, and converts the threshold value converted in the threshold value converter 208 to a constant DC value. Digital / Analog (hereinafter referred to as D / A) converter 210 for outputting in the form of an analog having a magnitude between the intensity output from the signal strength detector 202 and the signal transmitted from the D / A converter 210 The comparator 204 and the state detector 214 outputting the state information of the current signal level according to the result of the comparison in the comparator 204. In addition, the D / A converter 210 includes a pulse width modulator (hereinafter, referred to as PWM) 211 and a low pass filter 212.

The apparatus for detecting a state of a transmit / receive signal level configured as described above is applied to a receive path including an LNA 106, an RF amplifier 108, an IF amplifier 110, and an RX AGC 112 in the transmit / receive matching block shown in FIG. Can be. In more detail, the signal strength detector 202 of the state detection apparatus of the transmit / receive signal level has an output stage of the IF amplifier 110 in order to detect the strength of the signal of the stage where the influence of the front end is more prevalent than before. An input end is connected to the transmission path between the input ends of the RX AGC 112. The stage where the influence of the preposition is dominant means the stage which exists closer to the antenna 102. Therefore, the input terminal of the RX AGC 112 is a more predominant stage than the output terminal of the RX AGC 112. The signal strength detector 202 detects the strength of the signal in the same manner as the conventional envelope detection, and transmits the strength of the detected signal to the comparator 204.

The threshold value generator 206 is a means for generating a threshold value corresponding to the detection reference value of the signal to be detected, and may be implemented so that only one fixed value is generated or desired within an arbitrary range using an up / down counter. It may be implemented to set the reference value variably. The threshold converter 208 converts any threshold value generated by the threshold generator 206 into a form acceptable to the D / A converter 210 and transmits the converted threshold. For example, when a value equal to 3 dB is generated and transmitted by the threshold generator 206, the threshold converter 208 outputs a digital value (eg, '0011') corresponding to 3 dB. In order to operate in this manner, the threshold converter 208 may be implemented in a structure such as a ROM table.

As described above, the D / A converter 210 includes a PWM 211 and a low pass filter 212 to convert the digital value transmitted from the threshold converter 208 into an analog signal having a constant DC level. That is, when the digital value corresponding to the threshold value is transmitted from the threshold converter 208, the pulse width modulation is performed in the PWM 211, and then output at a constant DC level through the low pass filter 212. In this case, the PWM 211 may be replaced with a pulse duration modulation (PDM), and the low pass filter 212 has a structure using a resistor R and a capacitor C.

The comparator 204 compares the magnitude of the signal to be transmitted from the signal strength detector 202 with the magnitude of an analog signal having a constant DC level transmitted from the D / A converter 210, and according to the magnitude of '0'. Or outputs a logic signal of '1' to the state detector 214.

3 is an exemplary diagram of output waveforms of the signal strength detector 202, the D / A converter 210, and the comparator 204 shown in FIG. 2, where ① is an output waveform diagram of the signal strength detector 202, ② is an output waveform diagram of the D / A converter 210, and ③ is an output waveform diagram of the comparator 204.

As can be seen in the waveform diagram of FIG. 3, the comparator 204 is configured to have a logic high level when the intensity of the signal transmitted from the signal strength detector 202 is smaller than the threshold value transmitted from the D / A converter 210. Comparator 204 outputs a logic low ('0') when the signal output from the signal strength detector 202 is greater than the threshold transmitted from the D / A converter 210. Output the signal.

In addition, in FIG. 3, it can be seen that there is a chattering section in which a plurality of on / off cycles are repeatedly performed until the logic state of the output signal of the comparator 204 is clearly changed from logic high to logic low. This chattering period is generated due to the ripple noise carried in the output signal of the D / A converter 210 and the ripple noise carried in the output signal of the signal strength detector 202. Therefore, it is possible to adjust the pulse width of the above-mentioned chattering interval, which is not known the amount of ripple noise carried on the output signal of the signal strength detector 202, but the amount of ripple noise carried on the D / A converter 210 is PWM. This is because the output speed of 211 and the RC time constant constituting the low pass filter 212 can be known in advance. In other words, if the fluctuation range of the ripple noise is adjusted by changing the output speed of the PWM 211 or changing the R-C time constant constituting the low pass filter 212, the pulse width of the chattering section can be adjusted.

The state detector 214 is composed of a chattering detector 401 and a state machine 405 as shown in FIG. 4 to perform a function of outputting state information corresponding to a signal output from the comparator 204. .

That is, the chattering detection unit 401 included in the state detector 214 is composed of a delay circuit 4011, an exclusive OR element 4012, and a logic high detector 4013, and is output from the comparator 204. Detect a chattering interval as shown in. That is, the delay circuit 4011 delays the signal transmitted from the comparator 204 by an integral multiple of T = 1 / 2f ₀ (where f ₀ is a PWM output speed) and transmits the signal to the exclusive logical sum element 4012. The exclusive OR element 4012 outputs the result of the exclusive OR of the output signal of the comparator 204 and the output signal of the current comparator 204 delayed by an integer multiple of 1 / 2f ₀ in the delay circuit 4011. When the logic high detector 4013 detects a section in which the output signal of the comparator 204 remains high at a time period of T0 = 1 / 2f ₀ by the signal output from the exclusive OR circuit 4012, the section is chattered. Outputs a signal indicating that the transition region is generated.

The state machine 405 outputs the state information of the signal level to be currently detected according to the signal output from the logic high detector 4013 of the chattering detection unit 401 and the signal output from the comparator 204 as shown in Table 1 below. do.

State information of the signal level output as shown in Table 1 has a hysteresis characteristic as shown in FIG. That is, in the level detection and gain control unit 114, when the signal strength of the output terminal of the LNA 106 of FIG. 1 exceeds the RISE threshold of FIG. 5 by the state information of the signal level output from the state machine 405, the LNA 106. Lower the gain, and the transition area is set so that the lowered amount is sufficiently larger than the FALL threshold of FIG. In this state, when the signal strength of the input terminal of the LNA 106 decreases so that the detection amount for the received signal strength falls below the FALL, the level detection and gain control unit 114 maintains the gain of the LNA 106 to the maximum and thus the LNA 106. Adjust so that the output always maintains a level below a certain amount. That is, after the transition to low, the output of the transition state may be continuously detected according to the LNA 106 gain control.

However, when the intermodulation occurs, the strength detection amount of the received signal becomes larger than the RISE of FIG. 5, so the level detection and gain control unit 114 lowers the gain of the LNA 106 and increases the gain of the RX AGC 112 as it is lowered. To make it work. Then, in the normal case, the strength of the received signal passing through the LNA 106 gain and the RX AGC 112 gain is approximately equal at the time T = 0 and T = 1, so that the level detection and gain control unit 114 of FIG. The received signal strength detected by the signal becomes substantially constant.

However, if the received signal strength is detected larger than the normal signal due to the intermodulation state, the strength of the received signal increases above the RISE value to reduce the gain of the LNA 106. The unstable switching operation is repeated during the RX AGC 112 time constant period so that the intensity is drastically decreased so that the received signal strength detection amount suddenly drops below the FALL to increase the LNA 106 gain again. In order to overcome such an unstable switching operation, the LNA state machine in the level detection and gain control unit 114 operates in the intermodulation state and adjusts the time constant of the RX AGC 112 to quickly converge to a low or high state. The state of the signal level detection apparatus according to the present invention is to quickly detect the above-mentioned unstable switching phenomenon to notify the level detection and gain control unit 114 so that the above convergence is made faster.

6 illustrates a state of detecting an existing intermodulation state and a state in which an intensity detection amount of a received signal in FIG. 5 reacts according to the RISE or FALL threshold of FIG. 5.

As mentioned in the description of FIG. 5 described above, when the strength of the recognized signal according to the state information transmitted from the state machine 405 is less than the RISE threshold, the level detection and gain control unit 114 is the LNA 106. The gain is set to the maximum to operate in an operation mode that minimizes the noise figure, while maintaining the 'non-bypass state' to keep the reception level constant by adjusting only the RX-AGC 112 gain.

On the other hand, if it is recognized that the level of the signal currently received by the state information transmitted from the state machine 405 exceeds the RISE, the level detection and gain control unit 114 is the RX AGC 112 shown in FIG. The gain is set to 'bypass hold', which adjusts the LNA 106 gain while maintaining it. And, by operating a timer (not shown) provided therein transitions to a "bypass state" after a predetermined time.

When the detection amount detected by the signal strength detector 202 is greater than FALL until the timer (not shown) operation is completed, the level detection and gain control unit 114 maintains the 'bypass state'. Otherwise, the LNA 106 gain control is disabled and transitions to a non-bypass hold state. In the 'non-bypass maintaining state', a timer not shown is operated to set the time constant of the RX AGC 112 to be small for a predetermined time so that the response of the RX AGC 112 occurs quickly, thereby reducing the IM effect.

Meanwhile, the apparatus for detecting a state of a transmit / receive signal level according to the present invention implemented as shown in FIGS. 2 to 5 includes a PA 120 and a TX AGC 116 in a transmit / receive matching block shown in FIG. 1. Can be applied. More specifically, the signal strength detector 202 is connected to detect the strength of the transmitted signal transmitted through the stage existing between the output terminal of the PA 120 and the duplexer 104, which is more prevalent. The detector 214 transmits the state signal of the transmission signal level detected by the above-described method to the level detection and gain adjustment unit 114 so that the level detection and gain adjustment unit 114 takes into account the state of the transmission signal level. Allows the AGC 116 to adjust its gain.

As described above, the present invention provides a simple circuit configuration to detect the state of the transmit / receive signal level implemented to detect the state of the transmit / receive signal level in consideration of the characteristics of the transmit / receive end (or RF end) having the predominant front end effect. By providing a device, there is an advantage in that the gain on the transmit and receive path can be more accurately adjusted.

Claims (4)

An apparatus for detecting a level state of a signal transmitted through the reception path and the transmission path connected to each of a reception path and a transmission path of a transceiver for adjusting a gain of a signal, A signal strength detector for detecting the strength of the signal at the stage where the influence of the front end prevails on each of the reception path and the transmission path; A threshold converter for converting a predetermined threshold value in digital form; A converter for converting the digital threshold value converted by the threshold converter into an analog signal having a predetermined level and outputting the analog signal; A comparator for comparing a magnitude between the signal strength value detected by the signal strength detector and the value output from the converter; A state detector for detecting a state of a current level of a signal corresponding to the intensity detected by the signal strength detector according to the signal output from the comparator Transmitting and receiving signal level state detection device comprising a. The method of claim 1, And the predetermined threshold value can be set variably. The output of the comparator using the current output of the comparator and a signal delaying the output of the comparator by an integer multiple of 1 / 2f ₀ (f ₀ is the output speed of the converter). And a state machine which detects a transitioning chattering section, and outputs state information of the current level of the corresponding signal by using an output signal of the chattering detection unit and an output signal of the comparator. Device for detecting state of transmit / receive signal level. The digital / analog device of claim 1, wherein the converter comprises a pulse width modulator for modulating a pulse width of a digital threshold value converted by the threshold converter, and a filter for low-pass filtering a signal output from the pulse width modulator. Transmitter and signal level detection state characterized in that the converter.

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