KR100460498B1 - A device for protecting local oscillation frequency of up-down converter in transmitter - Google Patents

Abstract

The present invention relates to an up-down modulator of a base station transceiver for mobile communication, and more particularly, to an apparatus for effectively removing a local oscillation frequency classified as an undesired wave after modulation, comprising: an up-down modulator of a mobile communication base station transceiver; A local oscillator for generating and outputting an allocated local oscillation frequency; A splitter for dividing a signal output from the local oscillator into the same level and outputting the signal to each path; A mixer for mixing a local oscillation frequency output from one output terminal of the splitter and an input intermediate frequency signal to output a modulated signal at an assigned frequency; A phase shifter for shifting the phase of the local oscillation frequency output from the other output terminal of the splitter by 90 degrees and outputting the phase; A phase adjusting circuit which adjusts the phase of the signal output from the phase shifter by 90 degrees in the same direction and adjusts the phase shift of 180 degrees including the 90 degree phase shift of the phase shifter to be accurate; And a combiner which removes the local oscillation frequency and adds only the signal of the modulated frequency by adding the signal output from the mixer and the signal output from the phase adjusting circuit.

Description

Local oscillation frequency cancellation device for transceiving up-and-down converter {A DEVICE FOR PROTECTING LOCAL OSCILLATION FREQUENCY OF UP-DOWN CONVERTER IN TRANSMITTER}

The present invention relates to an up / down converter of a base station transceiver for a mobile communication, and more particularly, to effectively remove a local oscillation frequency (LOF) classified as a spurious wave after conversion (SPURIOUS FREQUENCY). Relates to a device.

The mobile communication system is a wireless communication using a frequency allocated between a mobile terminal or a mobile terminal communicating with a base station installed in a fixed place by wired connection to a mobile switching center. It is a wireless communication means that the spread is rapidly spread by the advantage that can be.

As described above, a base station (SITE) which performs wireless communication with a mobile terminal converts a low frequency signal or a medium frequency signal for communication from a subscriber into an allocated high frequency (RF) signal and simultaneously converts a signal that is wirelessly received at a high frequency into an intermediate frequency signal or a low frequency UP / DOWN CONVERTOR is used to convert the signal.

The up-and-down converter generates a high frequency (RF) signal of an allocated frequency by mixing the input low frequency signal or the intermediate frequency signal with a corresponding local oscillation frequency (LOF), and removes unnecessary unnecessary waves for transmission. While transmitting wirelessly through the antenna, the high frequency signal wirelessly received through the antenna is mixed with the local oscillation frequency (LOF) and converted into the required intermediate frequency signal or the low frequency signal, and the unnecessary unnecessary wave is removed and outputted. It is used as an information signal.

Eliminating unnecessary SPURIOUS in the up-and-down converter as described above is important for improving the performance and reliability of the wireless communication system. When using a filter, an unnecessary wave having a high input level LEVEL is generated. There was a problem that was difficult to remove completely.

Hereinafter, a local oscillation frequency removing device of a vertical transmission and reception converter according to the prior art will be described with reference to the accompanying drawings.

Attached to explain the prior art, FIG. 1 is a functional configuration diagram of a local oscillation frequency cancellation device of a vertical converter according to the prior art.

Referring to FIG. 1, the local oscillation frequency cancellation apparatus of the up-and-down converter for transmission and reception according to the prior art includes information (INFORMATION), the intermediate frequency (IF) input as an intermediate frequency (IF) signal. With signal (1),

LOCAL OSCILLATOR, which generates and outputs a local oscillation frequency to be modulated with the assigned high frequency signal by being mixed with the input intermediate frequency IF signal. 3) with,

MIXER which converts and modulates the input intermediate frequency signal 1 and the local oscillation frequency output from the local oscillator 3 into a signal having an assigned frequency by mixing 5,

A band pass filter (BPF) 7 which blocks and removes unnecessary signals by passing only signals in an allocated range among the signals output by the mixer 5 so as not to pass unnecessary SPURIOUS,

It is composed of a high frequency (RF) signal 9 which is wirelessly transmitted through an antenna as output from the band pass filter 7.

Hereinafter, a local oscillation frequency removal device of a transceiving up-down converter for transmitting and receiving according to the prior art having the above configuration will be described in detail with reference to the accompanying drawings.

The intermediate frequency signal 1 inputted with the information and the local oscillation frequency LOF output from the local oscillator 3 are applied to the mixer 5 and mixed to each other to be converted into a frequency in the allocated range. (CONVERSION) and MODULATION.

The local oscillation frequency LOF output from the local oscillator 3 is higher than the input intermediate frequency IF signal LEVEL.

The mixer 5 outputs a signal having an assigned frequency (IF + LOF) that is required by mixing an intermediate frequency (IF) signal and a local oscillation frequency (LOF) input, respectively, and at the same time, an unnecessary wave ( SPURIOUS) outputs the local oscillation frequency (LOF) of some levels by the mixed signal in the IF-LOF state and the high input level.

The output signal of the mixer 5 is applied to the band pass filter BPF 7 in order to pass only a signal of a band BAND required from the modulated signal output from the mixer 5 as described above.

The band pass filter (BPF) 7 passes only the modulated signal of the allocated band (BAND), and blocks or filters so as not to pass unwanted waves that are all frequencies other than the allocated band. Only the high frequency signal 9 of the said band is output.

When the SPURIOUS is output, the noise signal acts as a noise signal, and the output signal may be a high frequency signal 9 or a low frequency signal, but for convenience of description, it is set as a high frequency signal 9. Let's explain.

However, the local oscillation frequency removing device according to the prior art having the above-described configuration uses one band pass filter 7 as an undesired local oscillation frequency LOF having a high level LEVEL due to the characteristics of the band pass filter 7. There is a problem that is difficult to block or filter out the output,

If the bandpass filter 7 is used in a large number, the level of local oscillation frequency can be blocked or filtered due to the improvement to some extent, but the level of the corresponding high frequency signal to be output normally is low while the price is expensive. There is a problem of losing, and also, there is a problem of filtering unwanted waves from the signal on the MAIN PATH through which the signal is transmitted, and adding a noise signal generated by the band pass filter 7 itself without being filtered. .

The present invention is to prevent the local oscillation frequency inputted to the up-and-down converter to be output to the output stage, and to adjust the phase of the local oscillation frequency to be canceled by the phase of the local oscillation frequency to prevent the output of the high-level local oscillation frequency It is an object of the present invention to provide a local oscillation frequency canceling device.

The present invention has been made to achieve the above object, in the up and down converter of the mobile communication base station transceiver; A local oscillator for generating and outputting an allocated local oscillation frequency; A splitter for dividing the signal output from the local oscillator into the same level and outputting the signal to each path; A mixer configured to mix a local oscillation frequency output from one output terminal of the splitter and an input intermediate frequency signal and output a modulated signal at an assigned frequency; A phase shifter for shifting the phase of the local oscillation frequency output from the other output terminal of the splitter by 90 degrees and outputting the phase; A phase adjusting circuit which adjusts the phase of the signal output from the phase shifter by 90 degrees in the same direction and adjusts the phase shift of 180 degrees including the 90 degree phase shift of the phase shifter to be accurate; And a combiner outputting only a signal having a modulated frequency by removing the local oscillation frequency by adding the signal output from the mixer and the signal output from the phase adjusting circuit.

1 is a functional configuration diagram of a local oscillation frequency cancellation device of a vertical converter according to the prior art,

2 is a functional configuration diagram of a local oscillation frequency removal device of the up-down converter according to the present invention,

3 is a detailed functional configuration diagram of the phase adjustment circuit according to the present invention.

** Explanation of symbols on the main parts of the drawing **

1,10: intermediate frequency signal 3,20: local oscillator

5,40 Mixer 7: Bandpass Filter

9,80: high frequency signal 30: splitter

50: phase shifter 60: phase shift circuit

70: combiner 100: directional coupler

101: input port 102: output port

103: coupling port 104: separation port

110: first inductor 120: first varactor diode

130: second varactor diode 140: second resistor

150: third resistor 160: first resistor

170: condenser 180: second inductor

190: third varactor diode 200: fourth varactor diode

Hereinafter, a local oscillation frequency removal device of a transceiving up-down converter according to the present invention will be described with reference to the accompanying drawings.

2 is a functional configuration diagram of a local oscillation frequency removing device of the up-down converter according to the present invention, and FIG. 3 is a detailed functional configuration diagram of the phase adjustment circuit according to the present invention.

Referring to FIG. 2, the apparatus for canceling local oscillation frequency of a transceiving up-and-down converter according to the present invention includes an up / down converter of a base station transceiver which constitutes a mobile communication system.

An intermediate frequency signal (IF) 10 including input information to be transmitted from a subscriber registered in a mobile communication system (IF),

Local oscillator (LO: LOCAL OSCILLATOR) 20 which generates and outputs a local oscillation frequency (LOF) by fixedly generating the assigned designated frequency,

A splitter (30) for dividing the signal output from the local oscillator (20) into two of the same level (LEVEL) and outputting the signal to each corresponding path;

Mixed local oscillation frequency (LOF) output from one output terminal of the splitter 30 and the input intermediate frequency (IF) signal to convert to the assigned frequency (CONVERSION) and modulated (MODULATION) signal Mixer (MIXER) 40 to output,

A phase shifter 50 for shifting the phase PHASE of the local oscillation frequency LOF output from the other output terminal of the splitter 30 by 90 degrees and outputting the shifted phase PHASE;

A phase shift of 180 degrees including a 90 degree phase shift of the phase shifter 50 while shifting the phase PHASE of the signal output from the phase shifter 50 by 90 degrees in the same direction. A phase adjustment circuit 60 for outputting after being adjusted to be accurate; a local oscillation frequency LOF is removed by adding a signal output from the mixer 40 and a signal output from the phase adjustment circuit 60 The phase adjusting circuit 60 shifts the phase PHASE of the signal input to the input port 101 by 90 degrees, and outputs the THROUGHPUT PORT. Outputs the signal of the 90 degree phase shift with the level difference at the same time to the coupling port 103 and outputs the 180 degree phase shifted signal. Directional coupler (D) output to separation port (ISOL port) 104, respectively IRECTIONAL COUPLER 100; A first inductor (L1) 110 inserted into and connected between the separation port 104 of the directional coupler 100 and the ground (GROUND or EARTH); First and second varactor diodes (VARACTOR DIODE), each of which is connected to both ends of the first inductor 110 and whose capacitance of the capacitor is changed by a change in the applied level LEVEL of the voltage. (D1, D2) 120,130; A second resistor (R2) 140 commonly connected to the first and second varactor diodes (120, 130); A second inductor (L2) 180 connected between a coupling port 103 of the directional coupler 100 and a ground; The third and fourth varactor diodes D3 and D4 connected to both ends of the second inductor 180 and whose capacitance of the capacitor component changes due to a change in the level LEVEL applied to the voltage. 190,200); A third resistor (R3) (150) commonly connected to the third and fourth varactor diodes (D3, D4) (190, 200); The level LEVEL of the power supply voltage VCC applied to the second and third resistors 140 and 150 while being connected to the second and third resistors 140 and 150 at the same time is connected to the power supply voltage VCC. A first resistor R1 160 formed of a variable resistor; Condenser C1 170 is connected to the second and third resistors 140 and 150 so as to flow an AC signal applied from the first resistor 160 to the ground.

By adding the signal output from the mixer 40 and the signal output from the phase adjustment circuit 60, a local oscillation frequency (LOF) is removed to output only the corresponding high frequency (RF) signal 80 of the modulated frequency. It consists of a binner (COMBINER) 70.

Hereinafter, according to the present invention having the configuration described above, the up-down converter local oscillation frequency removal device of the mobile communication base station transceiver will be described in detail with reference to FIGS.

The local oscillator 20 generates the local oscillation frequency (LOF) of the assigned frequency stably and continuously, and continuously outputs it constantly. The local oscillation frequency (LOF) is constantly output from the local oscillator 20. Is applied to the splitter 30 and divided into two local oscillation frequency (LOF) signals of the same level LEVEL.

One of two local oscillation frequencies (LOFs) divided by the splitter 30 is output to the mixer 40, and the other is output to the phase shifter 50.

The mixer 40 receives and mixes both a local oscillation frequency (LOF) input from the splitter 30 and an intermediate frequency (IF) signal loaded with the information to be transmitted. A frequency FREQUENCY signal, that is, an up-converted high frequency RF signal is output to the combiner 70.

The mixer 40 may output a down-converted low frequency signal, and since the configuration of the up-modulation and down-modulation functions are the same, in the description of the present invention, for example, high frequency (RF) A process of outputting a signal 80 will be described, and a process of outputting a low frequency signal will be omitted.

In addition, the phase shifter 50 shifts or shifts the phase PHASE of the LOF signal output from the splitter 30 by 90 degrees, and then applies it to the phase adjustment circuit 60. do.

The phase adjustment circuit 60 applies a local oscillation frequency (LOF) inputted by a 90 degree phase shift or phase shift to the input port 101 of the directional coupler 100.

The signal applied to the input port 101 of the directional coupler 100 further generates a 90-degree phase shift or phase shift while simultaneously inputting the majority of the power (POWER), for example, About 4/5 of the input power is output to the output port (THROUGH PORT) 102, the remaining some level of power (POWER), for example, about 1/5 of the input power is the coupling port (COUPLING PORT) ( The signal of some power which is outputted to the output port 102 and not output to the output port 102 is reflected, and again, the separation port in the state where a phase shift or phase shift of 90 degrees occurs. 104).

The phase shift or phase shift is also referred to as phase delay.

That is, the phase PHASE of the LOF signal output to the output port 102 of the directional coupler 100 is output from the local oscillator 20 and is separated and output by the splitter 30. When compared with the phase (PHASE) of the LOF signal, a total of 180 degrees of phase shift or phase shift occurs.

However, the phase shift or phase shift as described above does not occur exactly 180 degrees from the phase of the signal output from the splitter 30 at the output port 102, so that a slight error DIFFERENCE occurs. Correcting the same fine error DIFFERENCE is performed by the remaining components of the phase adjusting circuit 60.

The separation port 104 of the directional coupler 100 is formed by combining the first inductor 110, the first and second varactor diodes 120 and 130, the second resistor 140, and the first resistor 160. The coupling port 103 is connected to the second inductor 180, the third and fourth varactor diodes (190, 200) by the combination of the third resistor 150 and the first resistor 160 is connected do.

The first resistor 160 is a variable resistor connected to a power supply voltage VCC. The first resistor 160 adjusts a level of a voltage applied to the second resistor 140 and the third resistor 150, and controls the capacitor. 170 is applied from the power supply voltage VCC, and blocks unwanted wave components by flowing all signals of AC which become noise signals to ground (GROUND or EARTH).

The voltage input in a state regulated by the first resistor 160 may be controlled by the first and second varactor diodes 120 and 130 and the third and fourth varactor diodes through the second and third resistors 140 and 150. 190 and 200, respectively.

The VARACTOR DIODEs D1, D2, D3, and D4 are variable capacitance diodes whose capacitance is changed by a change in applied voltage.

The second and third resistors 140 and 150 are different from each other in power levels of signals output from the coupling port 103 and the separation port 104, and are used to compensate for the level difference. The power supply voltage VCC supplied by the first resistor 160 is applied to the first to fourth varactor diodes D1, D2, D3, and D4 through the second and third resistors 140 and 150. Change the (CAPACITANCE) value.

As described above, the circuit configuration connected to the coupling port 103 and the separation port 104, respectively, is compensated for by the difference in power level and corresponds to the LC circuit formed by the varactor diode and the inductor whose capacitance is variable. The phase of the local oscillation frequency signal output to the coupling port 103 and the separation port 104 is changed, and the signal output to the corresponding port PORT is not output and is reflected.

The local oscillation frequency (LOF) signal reflected from each coupling port 103 and separation port 104 as described above is output to the output port 102 of the directional coupler 100. This adjusts or adjusts the phase of the (LOF) signal.

That is, by adjusting or adjusting the first resistor 160, the output resistance value is varied, and the variable resistance value as described above is applied to each varactor diode by adjusting the power supply voltage VCC. Thus, the control value of the LC circuit consisting of the barracter diode and the inductor is adjusted or adjusted, and the respective coupling port 103 and the separation port 104 are connected to the corresponding local oscillation frequency by the LC value adjusted or adjusted as described above. By reflecting the LOF, the reflected local oscillation frequency (LOF) signal as described above adjusts or adjusts the phase PHASE of the signal output to the output port 102.

Therefore, by controlling the phase adjusting circuit 60, the difference between the phase PHASE of the signal output from the splitter 30 and the phase PHASE output from the phase adjusting circuit 60 is exactly 180 degrees. To occur.

Accordingly, a local part output from the splitter 30 and applied to the mixer 40 to convert the intermediate frequency IF signal from the outside into a corresponding RF signal, and converts and modulates the signal into a corresponding RF signal. The oscillation frequency (LOF) signal is applied to the combiner 70 together with the high frequency (RF) signal.

In addition, the signal output from the phase adjustment circuit 60 outputs a local oscillation frequency (LOF) signal having a phase difference (PHASE DIFFERENCE) of exactly 180 degrees with a local oscillation frequency (LOF) signal output from the splitter 30. The output signal is applied to the combiner 70.

The combiner 70 accurately corrects a phase PHASE of a local oscillation frequency (LOF) signal input through the mixer 40 and a local oscillation frequency (LOF) signal input through the phase adjustment circuit 60. Since the difference is 180 degrees, the LOF signals cancel each other out.

In addition, the local oscillation frequency (LOF) signals, which are separated into two signals of the same power level (POWER LEVEL) by the splitter 30 and output, are 180 degrees out of phase so that the combiner 70 Coupled and canceled with each other, the problem of power level differences does not occur.

The signal output from the combiner cancels the local oscillation frequency (LOF) signal induced by the output due to the high power level (POWER LEVEL) and outputs only the modulated high frequency signal (80).

When the LOF signal is not canceled and is output together with the corresponding high frequency signal, the LOF signal acts as a noise signal, which is a SPURIOUS signal, so as to demodulate the information signal to be transmitted. Difficulties occur at the same time, and the demodulation equipment becomes complicated, which leads to high cost and volume.

Such a configuration has the same function by the same configuration even when outputting a low frequency signal.

The present invention having the above configuration completely removes the local oscillation frequency signal of the up-down modulator and outputs only the modulated information signal without a noise signal, thereby improving the reliability of the system.

In addition, since a combiner or the like, which is relatively inexpensive than the bandpass filter, is used, the system price is lowered, and since a noise signal that is secondarily excited by the bandpass filter is not generated, the demodulation circuit can be easily configured. There is an industrial use effect.

Claims (2)

In the up and down modulator of the mobile communication base station transceiver, A local oscillator for generating and outputting an allocated local oscillation frequency; A splitter for dividing the signal output from the local oscillator into the same level and outputting the signal in each path; A mixer configured to mix a local oscillation frequency output from one output terminal of the splitter and an input intermediate frequency signal and output a modulated signal at an assigned frequency; A phase shifter for shifting the phase of the local oscillation frequency output from another output terminal of the splitter by 90 degrees and outputting the phase; A phase adjusting circuit for shifting the phase of the signal output from the phase shifter by 90 degrees in the same direction and simultaneously outputting the phase shift of 180 degrees including the 90 degree phase shift of the phase shifter to be accurate; Removing the local oscillation frequency by adding a signal output from the mixer and a signal output from the phase adjusting circuit to remove a local oscillation frequency and output only a signal having a modulated frequency. Device. The method of claim 1, wherein the phase adjustment circuit, Directional to shift the phase of the signal input to the input port 90 degrees to the output port, and output the 90-degree phase shift signal having a level difference to the coupling port, and outputs the 180-degree phase shifted signal to the separation port, respectively With combiner, A first inductor connected between the separation port of the directional coupler and a ground; First and second varactor diodes connected to both ends of the first inductor, the capacitor capacitance of which is changed depending on the level of voltage applied thereto; A second resistor commonly connected to the first and second varactor diodes, A second inductor connected between a coupling port of the directional coupler and a ground; Third and fourth varactor diodes connected to both ends of the second inductor, the capacitor capacitance of which is changed by a level of voltage applied thereto; A third resistor commonly connected to the third and fourth varactor diodes, A first resistor made of a variable resistor connected to the second and third resistors at the same time and connected to a power supply voltage to adjust a level of the power supply voltage applied to the second and third resistors; And a capacitor which is connected to the second and third resistors in common and flows an AC signal applied from the first resistor to the ground.