KR100401196B1 - Method and apparatus for bypass i/q mixer in frequency modulation mode of dual cdma mobile communication equipment - Google Patents

Abstract

The present invention relates to an apparatus and method for bypassing an intermediate frequency signal in an FM mode in an I, Q mixer in a mobile communication terminal having an FM mode and a CDMA mode, and filtering the I communication signal to a frequency suitable for CDMA processing. A first CDMA low pass filter, a second CDMA low pass filter for filtering a Q communication signal to a frequency suitable for CDMA processing, an FM low pass filter for receiving the Q communication signal in a FM mode and filtering at a predetermined frequency suitable for FM; In the CDMA mode, the I mixer receives the filtered I communication signal and the predetermined local oscillation frequency and generates and outputs a first intermediate frequency. In the CDMA mode, the filtered Q communication signal and the predetermined local oscillation frequency are used. A Q mixer for generating and outputting a second intermediate frequency, and receiving the filtered signal from the FM low pass filter; A local oscillation frequency generating unit generating a frequency, a phase shifting unit applying the second oscillation frequency to the second CDMA low-pass filter by phase shifting the local oscillating frequency, the phase shifting unit and the in-phase mixer simultaneously operating the local oscillating frequency. A node for providing a switch, a switch unit for switching the local oscillation frequency to an output terminal of the node or the Q mixer under predetermined control, the first and second CDMA low-pass filters, an I mixer, a Q mixer, and a switch unit in FM mode. And a mode selector for disabling the FM low pass filter in the CDMA mode.

Description

In-phase and Quadrature Phase Mixer Bypass Device and Method in Frequency Modulation Mode of Dual-Mode Code Division Multiple Processing Mobile Communication Terminals

The present invention relates to an apparatus and method for generating an intermediate frequency of a mobile communication terminal having a frequency modulation mode and a code division multiple access ("CDMA") mode, and in particular, frequency modulation (hereinafter referred to as "FM"). An apparatus and method are provided for bypassing an in-phase and quadrature phase mixer (Mix) in an intermediate frequency signal in a "

Typically, the dual mode (FM mode and CDMA mode) mobile communication terminal is set differently from the FM mode and the CDMA mode. The FM mode is an analog mode, and the CDMA mode is a digital mode. The analog mode FM mode operates in the same manner as the conventional E-AMPS.

The dual mode mobile communication terminal receives a digital signal from a mobile station modem (MSB), converts it into an analog signal, passes the low pass filter, and then the in-pager. The intermediate frequency is generated through an inphase / quadrature mixer (hereinafter referred to as "I / Q mixer"). In the case of the CDMA method, an intermediate frequency signal is generated using both I / Q mixers. In the case of the FM system, the I / Q mixer does not function properly. However, in the case of the FM system, the I / Q mixer operates without any function.

As described above, although the I / Q mixer does not perform a proper function in the frequency modulation mode, there is a problem in that unnecessary current is consumed.

Accordingly, an object of the present invention is to provide an apparatus and method for directly bypassing an in-phase and quadrature phase mixer from baseband analog to an output stage of an in-phase and quadrature phase mixer when generating an intermediate frequency in a frequency modulation mode. .

In order to achieve the above object, the present invention provides a dual mode code division including an in-phase digital / analog converter and a quadrature digital / analog converter for converting and outputting predetermined data into an in-phase communication signal and a quadrature communication signal. A multi-processing mobile communication terminal, comprising: a first code division multiple processing low pass filter for filtering the in-phase communication signal to a frequency suitable for code division multiple processing, and a quadrature communication signal filtering to a frequency suitable for code division multiple processing A second code division multiple processing low pass filter, a frequency modulation low pass filter which is enabled in a frequency modulation mode selected by a predetermined control, and receives the quadrature communication signal and filters it to a predetermined frequency suitable for frequency modulation; Enabled in the code division multiple processing mode selected by the predetermined control, An in-phase mixer configured to generate an intermediate frequency by receiving a filtered in-phase communication signal and a predetermined local oscillation frequency, and to be enabled in the code division multiple processing mode, and to enable the filtered quadrature communication signal and a predetermined A quadrature mixer which generates a local frequency by receiving a local oscillation frequency and outputs a local oscillation frequency signal for dual mode by receiving a filtered signal from the frequency modulated low pass filter by receiving a predetermined AC voltage. A frequency generator, a phase shifter for phase shifting the local oscillation frequency signal to the quadrature mixer, and a node for simultaneously simultaneously providing the local oscillation frequency signal to the phase shifter and the in-phase mixer in parallel; A connection between the local oscillation frequency generator and the node and the quadrature mixer output stage; A switch unit for switching the local oscillation frequency to the node and the quadrature mixer output stage under a predetermined control, an inverter for inverting the input signal and outputting the frequency modulated low pass filter, and receiving a predetermined mode selection signal from the outside Outputting a control signal to the first and second code division multiple processing low pass filter, an in-phase mixer, a quadrature mixer, and a switch unit, and outputting the control signal to a frequency modulated low pass filter through the phase shifter to operate in a corresponding mode; Characterized in that it consists of a mode selection unit.

In order to achieve the above object, the present invention provides an in-phase mixer, a quadrature mixer, a local oscillation frequency generator, a node, a local oscillation frequency generator, and a node and a quadrature mixer output stage. In the in-phase and quadrature phase mixer bypass method in the frequency modulation mode of the dual mode code division multiple processing mobile communication terminal having a control unit for switching the local oscillation frequency to the node and quadrature mixer output stage under control, A first process of checking whether a predetermined mode selection signal is input from an external source, a second process of determining whether a mode modulation signal is a frequency modulation mode selection signal when the mode selection signal is input, and the mode selection signal is a frequency modulation mode selection signal; When determined, the switch unit is switched to the quadrature mixer output stage to generate the local oscillation frequency. A third step of directly outputting the local oscillation frequency signal output from the to the quadrature mixer output stage; and if the mode selection signal is determined to be a code division multiple processing mode selection signal, the switch unit switches to the node to perform the in-phase And a fourth process of generating the first and second intermediate frequency signals through the mixer and the quadrature mixer.

1 is a block diagram of a transmitter in a mobile communication terminal according to an embodiment of the present invention.

2 is a flowchart illustrating a mixer bypass method in a frequency modulation mode of a mobile communication terminal according to an embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. First, in adding reference numerals to the components of each drawing, it should be noted that the same reference numerals have the same reference numerals as much as possible even if displayed on different drawings. In the following description of the present invention, if it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

1 is a block diagram of a transmitter of a mobile communication terminal according to an exemplary embodiment of the present invention.

Referring to FIG. 1, an in-phase digital / analog converter (I DAC) 101 converts a digital signal input from a mobile station modem (MSM) into an in-phase signal (hereinafter referred to as "I communication signal") which is an analog signal. To print. The quadrature digital / analog converter (Q DAC) 102 is a quadrature signal, which is an analog signal (hereinafter referred to as a “Q communication signal”), of a digital signal input from a mobile station modem (MSM) like the in-phase digital / analog converter 101. Convert to and print it out. The first code division multiple processing low pass filter (CDMA LPF) 104 is enabled by a predetermined control signal provided from the mode selection unit 108 to receive and filter the I communication signal, and the second code division multiple processing low pass filter 103 It is enabled by the same control signal as the predetermined control signal input to the first code division multiple processing low pass filter 104 to receive and filter the Q communication signal. The output frequency filtered by the first and second code division multiple processing low pass filters 103 and 104 has a range of ± 630 KHz with respect to 0 Hz. The in-phase mixer 109 is enabled by receiving the same control signal as the control signal input from the first and second code division multiple processing low pass filters 103 and 104, and the first code division multiple processing low pass filter. A first intermediate frequency is generated by adding an I communication signal output from 104 and a predetermined local oscillation frequency. The in-phase mixer 109 outputs the generated first intermediate frequency to an RF stage (not shown). The quadrature mixer 111 is configured to receive the control signal and to enable the Q signal and to output the Q communication signal output from the second code division multiple processing low pass filter 103 and the local oscillation frequency to a predetermined phase. The input is mixed to generate a second intermediate frequency signal. The second intermediate frequency signal is also output to the RF stage.

A frequency modulated low pass filter (FM LPF) 105 is enabled by a control signal opposite to a control signal input to the first and second code division multiple processing low pass filters 103 and 104, and receives the Q communication signal for frequency modulation. Filter by the right frequency. At this time, the output frequency of the filtered signal has a range of ± 15KHz around 0Hz. The filtered signal is transmitted to the local oscillation frequency generator 120. The local oscillation frequency generator 120 receives an AC signal output from an external phase lock loop (PLL) (not shown), receives a signal filtered by the frequency modulated low pass filter 105, and is required for dual mode. Generate local oscillation frequency. To this end, the local oscillation frequency generator 120 includes a loop filter 116, a tank circuit 115, a voltage controlled oscillator 114, and a 1/2 divider 113.

The operation of the local oscillation frequency generator 120 will be described in more detail below.

The loop filter 116 receives an AC signal output from an external phase synchronization loop, and outputs a constant DC component by controlling noise and high frequency components of the signal. The tank circuit 115 has a resonance frequency determined by the voltage output from the loop filter 116, and converts the Q communication signal of ± 15KHz output from the FM low pass filter 105 into 260.76MHz. The voltage controlled oscillator 114 amplifies and outputs the 260.76 MHz signal generated by the determined resonance frequency. The 1/2 divider 113 divides the frequency of the 260.76 MHz signal in half and outputs a local oscillation frequency signal of 130.38 MHz.

The local oscillation frequency signal output from the 1/2 divider 113 is input to the in-phase mixer 109 at the node 117. The node 117 simultaneously inputs the local oscillation frequency signal to the phase shifter 110 and the in-phase mixer 109 in parallel. The phase shifter 110 phase shifts the local oscillation frequency signal by 90 ° and outputs the phase shifter to the quadrature mixer 111.

The switch unit 112 is connected between the 1/2 divider 113 and the node 117 and receives a predetermined control signal provided from a mode selector 108 and outputs a signal output from the 1/2 divider to the node 117 or the quad. Switch selectively to the output of mixer 111.

The mode selector 108 transmits control signals to the first and second code division multiple processing low pass filters 104 and 103 and the in-phase mixer 109, quadrature mixer 111 and the switch unit 112 according to the selected mode (CDMA mode or FM mode). Output and operate in the relevant mode. The control signal is configured in a toggle form.

For example, if the CDMA mode is selected, the mode selector 108 outputs high or low to select the CDMA mode. When the control signal is called high, it is the first and second code division multiple processing low pass filters 103 and 104, the in-phase mixer 109, and the quadrature mixer 111 that receive and operate the control signal. The control signal is output to the switch unit 112 to switch the switch unit to the node 117. On the other hand, since the FM low pass filter 105 toggles the control signal through the inverter 107, the control signal becomes low and is disabled. In this case, the frequency output from the in-phase mixer 109 outputs a signal spread by ± 630 KHz with respect to 130.38 MHz. That is, a baseband signal of ± 630 KHz is placed on a signal of 130.38 MHz output from the 1/2 divider 113.

If the FM mode is selected, the mode selector 108 outputs a low signal. The low signal disables the first and second code division multiplexing low pass filters 103 and 104, the in-phase mixer 109 and the quadrature mixer 111 related to the CDMA mode. The low signal is then inverted to a high signal at the inverter 107 to operate (enable) the RF low pass filter. In addition, the low signal is input to the switch unit 112 to switch the signal output from the 1/2 divider 113 to the output stage of the quadrature mixer 111. At this time, the frequency output to the RF stage is not only 130.38MHz, but has a deviation of 15KHz based on this frequency. That is, the DC voltage generated by the loop filter 116 and the AC voltage output from the FM low pass filter 105 are combined to generate resonance and modulation simultaneously in the tank circuit 115. As a result, the signal passing through the tank circuit 115 does not need to go through the mixer, so it is directly transmitted from the output of the quadrature mixer 111 to the RF stage.

2 is a flowchart illustrating a mixer bypass method in a frequency modulation mode of a mobile communication terminal according to an embodiment of the present invention.

Referring to FIG. 2, first, in step 201, the mode selector 108 checks whether a mode selection signal is input. In this case, when the mode selection signal is input, the mode selection unit 108 proceeds to step 203 and determines whether the mode selection signal is the FM mode selection signal. If it is determined that the FM mode selection signal, the mode selector 108 proceeds to step 205 and outputs a low signal under the assumption. In this case, the low signal is the first and second code division multiple processing low pass filter 104, 103, which is a CDMA mode processor. Input to in-phase mixer 109 and quadrature mixer 111 to disable. The low signal is also inverted by phase shifter 107 to operate (enable) the FM low pass filter 105. At this time, the Q communication signal output from the quadrature digital / analog converter 102 is converted into a modulated FM signal having a frequency of 130.38 MHz through the tank circuit 115, the voltage controlled oscillator 114, and the 1/2 frequency divider 113, and the modulated FM signal. Is input to the switch section 112. In operation 207, the switch unit 112 receives a low signal from the mode selector 108 and switches to the output terminal of the quadrature mixer 111. Accordingly, the modulated FM signal is directly output to the RF stage without passing through the in-phase mixer 109 and the quadrature mixer 111.

In contrast, if the mode selection signal is not the FM mode selection signal in step 203, it is determined whether the mode selection signal is the CDMA mode selection signal in step 209. If it is not the FM mode selection signal, it will be a CDMA mode selection signal. When the CDMA mode selection signal is input, the mode selector 108 proceeds to step 211 to disable the FM low pass filter 105, and the first and second code division multiple processing low pass filters 104 and 103, the in-phase mixer 109 and the quadrature mixer. Enable 111. In operation 213, the mode selector 108 outputs a high signal to the switch 112 to switch to the node 117. Therefore, the in-phase mixer 109 receives the filtered signal output from the first code division multiple processing low pass filter 104, and is input through the loop filter 116, the tank circuit 115, the voltage controlled oscillator 114, and the 1/2 divider 113. Mixed with to produce a first intermediate frequency. The quadrature mixer 111 receives the filtered signal output from the second code division multiple processing low pass filter 103, and receives the signal input through the loop filter 116, the tank circuit 115, the voltage controlled oscillator 114, and the 1/2 divider 113. The phase shifter 110 mixes the 90 ° phase shifted signal to generate a second intermediate frequency. The first and second intermediate frequencies generated by the in-phase mixer 109 and the quadrature mixer 111 are transmitted to the RF stage.

As described above, since the present invention can generate an intermediate frequency without passing through the in-phase / quadrature mixer, there is an advantage of saving unnecessary current when the in-phase / quadrature mixer is operated in the frequency modulation mode. .

Claims (4)

In a dual mode code division multiple processing mobile communication terminal comprising an in-phase digital / analog converter and a quadrature digital / analog converter for converting and outputting predetermined data into an in-phase communication signal and a quadrature communication signal, A first code division multiple processing low pass filter for filtering the in-phase communication signal to a frequency suitable for code division multiple processing; A second code division multiple processing low pass filter for filtering the quadrature communication signal to a frequency suitable for code division multiple processing; A frequency modulated low-pass filter enabled in a frequency modulation mode selected by a predetermined control, the frequency modulated low-pass filter receiving the quircher communication signal and filtering the predetermined frequency according to the frequency modulation; An in-phase mixer which is enabled in a code division multiple processing mode selected by a predetermined control, generates an intermediate frequency by receiving the filtered in-phase communication signal and a predetermined local oscillation frequency, and outputs the intermediate frequency; A quadrature mixer enabled in the code division multiple processing mode and generating an intermediate frequency by receiving the filtered quadrature communication signal and a predetermined local oscillation frequency; A local oscillation frequency generator for receiving a predetermined AC voltage and receiving a filtered signal from the frequency modulated low pass filter to generate a local oscillation frequency signal for dual mode; A phase shifter which phase shifts the local oscillation frequency signal and applies the phase shifter to the quadrature mixer; A node for simultaneously providing the local oscillation frequency signal in parallel to the phase shifter and the in-phase mixer; A switch unit connected between the local oscillation frequency generator and the node and the quadrature mixer output stage and switching the local oscillation frequency to the node and the quadrature mixer output stage under predetermined control; An inverter for inverting an input signal and outputting the inverted signal to the frequency modulated low pass filter; Receives a predetermined mode selection signal from the outside and outputs a control signal to the first and second code division multiple processing low pass filter, in-phase mixer, quadrature mixer, and switch unit, and transmits the control signal to the frequency modulated low pass filter through the inverter. An in-phase and quadrature phase mixer bypass device in a frequency modulation mode of a dual mode code division multiple processing mobile communication terminal, characterized by consisting of a mode selector for outputting the signal to operate in a corresponding mode. The method of claim 1, wherein the local oscillation frequency generating unit, A loop filter which receives a predetermined AC voltage and converts the same into a predetermined DC voltage, and outputs the same; A tank circuit operated by the DC voltage and receiving a filtered signal from the frequency modulated low pass filter to determine a resonance frequency; A voltage controlled oscillator for amplifying and outputting a desired frequency by the resonance frequency; In the frequency modulation mode of the dual mode code division multiple processing mobile communication terminal, characterized in that it consists of a 1/2 divider for dividing the frequency of the signal output from the voltage-controlled oscillator into 1/2 to output the local oscillation frequency signal. -Phase and quadrature phase mixer bypass device. The dual mode code division multiple processing of claim 1, wherein the local oscillation frequency output to the output terminal of the quadrature mixer is an intermediate frequency when the switch unit switches to the output terminal of the quadrature mixer in the frequency modulation mode. In-phase and quadrature phase mixer bypass device in the frequency modulation mode of the communication terminal. An in-phase mixer, a quadrature mixer, a local oscillation frequency generator, a node, a local oscillation frequency generator, and a node and a quadrature mixer output stage are connected to each other, and the local oscillation frequency In the in-phase and quadrature phase mixer bypass method in the frequency modulation mode of a dual mode code division multiple processing mobile communication terminal having a switch unit for switching to a quadrature mixer output stage, A first process of checking whether a predetermined mode selection signal is input from the outside; A second process of determining whether a frequency modulation mode selection signal is input when the mode selection signal is input; A third process of directly switching the switch unit to the quadrature mixer output stage when the mode selection signal is the frequency modulation mode selection signal and outputting the local oscillation frequency signal output from the local oscillation frequency generator to the quadrature mixer output stage; and, If it is determined that the mode selection signal is a code division multiple processing mode selection signal, a fourth process of generating the first and second intermediate frequency signals through the in-phase mixer and the quadrature mixer is performed by switching the switch unit to the node. How to feature.