KR20030007350A - GPS signal and CDMA signal separate receiver of mobile phone - Google Patents

Abstract

PURPOSE: A device for separately receiving a GPS signal from a CDMA signal of a mobile communication terminal is provided to apply a DBA(Dual Band Antenna) and an RF switching circuit to a CDMA terminal, thereby separately receiving the GPS and the CDMA signals. CONSTITUTION: An RF switching circuit(200) is configured between a DBA(100) and the first/second antenna matching circuits(23,24), and separates a GPS signal from a CDMA signal received from the DBA(100). The RF switching circuit(200) has one input port and two output ports to guide the GPS signal to the first antenna matching circuit(23), and to guide the CDMA signal to the second antenna matching circuit(24), as performing on/off switching operations. The on/off switching operations of the RF switching circuit(200) are controlled by digital control signals outputted through a GPIO of a modem chip(300) according to GPS and CDMA communication modes. The RF switching circuit(200) is configured in an SPDT(Single Pole Double Throw) type composed of parallel diodes or transistors, to determine streams of the GPS signal and the CDMA signal by being turned on according to levels of the digital control signals when the different digital control signals are inputted.

Description

GPS signal and CDMA signal separate receiver of mobile communication terminal {GPS signal and CDMA signal separate receiver of mobile phone}

The present invention relates to a transmission and reception circuit of a mobile communication terminal, and in particular, by applying a dual band antenna (DBA) and an RF (Radio Frequency) switching circuit to a CDMA terminal to receive GPS and CDMA signals more effectively. The present invention relates to a GPS and CDMA signal separation receiver of a mobile communication terminal.

As is well known, currently commercially available communication services are classified into CDMA services of 800 MHz band, GPS services of 1575.42 MHz band, and PCS services of 1.7-1.9 GHz band. It was configured.

That is, the transmission and reception circuit of the terminal for receiving the CDMA and GPS and PCS services, as shown in Figures 1 and 2, the first and second GPS band filter (1a) (1b), filtering the frequency of the GPS band, filtering GPS band signal low noise amplifier (2), GPS band frequency down mixer (3), receiving digital demodulation circuit IC (4), duplexer (5) for transmitting and receiving signal separation, CDMA band signal low noise amplifier (6), CDMA receive band filter (7), CDMA band frequency down mixer (8), phase locked loop (PLL) circuit for GPS and CDMA band local frequency signal synthesis (9), digital modulation circuit IC 10 for transmission, CDMA band frequency up mixer 11, CDMA band output amplifier 12, CDMA transmission band filter 13, CDMA band high output amplifier 14 Is commonly applied.

At this time, the service having the frequency band as described above can be used through one terminal.

In the case of a terminal receiving a GPS service, as shown in FIG. 1, the first antenna 21 for GPS and the second antenna 22 for CDMA, the first antenna matching circuit 23 for GPS, and the second for CDMA are internal and external types. An antenna matching circuit 24 is applied.

In case of a terminal receiving CDMA service, as shown in FIG. 2, a dual band antenna having a diplexer 31, a third antenna matching circuit 32, and two frequency band characteristics (GPS / CDMA) 100) was applied.

However, as shown in FIG. 1, when the built-in first antenna 21 is used, not only a problem of sensitivity deterioration occurs, but the first and second antennas 21 and 22 are formed in the built-in type and the external type, respectively. Due to the double cost, the manufacturing cost for the terminal has increased, and the application of the dual antennas 21 and 22 has caused considerable difficulties in the arrangement of components in the terminal.

On the other hand, when using the diplexer 31 as shown in Fig. 2, the application is mainly limited to terminals receiving CDMA services, and insertion loss in terminals of PCS services adjacent to the frequencies of GPS and CDMA services. Due to this excessive occurrence, this has caused difficulties in manufacturing the diplexer 31, and thus, the diplexer 31 as described above cannot be applied to the current PCS terminal.

Accordingly, an object of the present invention is to solve the above-described problems, and an object of the present invention is to provide dual band antenna and RF switching to a CDMA terminal in consideration of the fact that the terminal does not use CDMA service when operating in GPS mode. By applying the circuit, GPS and CDMA signals can be separated and received more effectively, and insertion loss is prevented when constructing a CDMA terminal circuit in a band adjacent to the GPS band, especially PCS. It is intended to provide a GPS and CDMA signal separation receiver of a mobile communication terminal which eliminates the use of a built-in antenna that does not have good characteristics and reduces the manufacturing cost of the terminal according to the circuit configuration while eliminating the difficulty of arranging components in the terminal. will be.

1 is a transmission and reception circuit diagram of a mobile communication terminal for separating GPS and CDMA signals using an antenna having two frequency band characteristics.

2 is a circuit diagram of a mobile communication terminal for separating GPS and CDMA signals using a conventional diplexer.

3 is a transmission and reception circuit diagram of a mobile communication terminal for separating GPS and CDMA signals using a dual band antenna and an RF switching circuit according to an embodiment of the present invention.

4 is a detailed diagram of an SPDT type RF switching circuit for separately receiving GPS and CDMA signals according to an embodiment of the present invention.

5 and 6 are detailed views of an SPST type RF switching circuit for separately receiving GPS and CDMA signals according to another embodiment of the present invention.

* Description of the symbols for the main parts of the drawings *

23,24; First and second antenna matching circuits 100; Dual Band Antenna

200; RF switching circuit 300; Modem chip

D1, D2, D3; diode

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

For reference, the drawings referred to below will be described with the same reference numerals for the same parts as in the prior art for convenience of description.

3 is a transmission and reception circuit diagram of a mobile communication terminal for separating GPS and CDMA signals using a dual band antenna and an RF switching circuit according to an embodiment of the present invention, and FIG. 4 is a diagram illustrating GPS and CDMA signals according to an embodiment of the present invention. The detailed figure of SPDT type RF switching circuit which receives separately.

3 and 4, the first and second GPS band filters 1a and 1b for filtering the frequency of the GPS band, the GPS band signal low noise amplifier 2 for amplifying the frequency of the filtered GPS band, GPS band frequency downmixer (3), receiving digital demodulation circuit IC (4), duplexer (5) for transmitting / receiving end signal separation, CDMA band signal low noise amplifier (6), CDMA receiving band filter (7), CDMA band frequency downmixer 8, PLL circuit 9 for GPS and CDMA band local frequency signal synthesis, digital modulation circuit IC 10 for transmission, CDMA band frequency upmixer 11, CDMA band output amplifier 12 In a transmission / reception circuit of a conventional CDA (CDMA) terminal to which a CDMA transmission band filter 13 and a CDMA band high power amplifier 14 are applied,

The dual band antenna 100 having two frequency band characteristics, the first antenna matching circuit 23 for GPS and the second antenna matching circuit 24 for CDMA are applied to the transmission / reception circuit of the PCS terminal.

Between the dual band antenna 100 and the first and second antenna matching circuits 23 and 24, a GPS signal received from the dual band antenna 100 and a CDMA signal are separated and the GPS signal is matched to the first antenna. Configures an RF switching circuit 200 having on / off switching with one input port and two output ports to guide the circuit 23 and the CDMA signal to the second antenna matching circuit 24,

The on / off switching of the RF switching circuit 200 is controlled by a digital control signal output through the general-purpose digital input / output port (GPIO) of the modem chip 300 according to the GPS and CDMA communication mode.

According to another aspect, the RF switching circuit 200 is shown in Figure 4,

When digital control signals of different patterns are input through parallel bias ports (bias1) and (bias2), the flow of GPS signals and CDMA signals is turned on according to the level of the input digital control signals. It is characterized by consisting of a single PoleDouble Throw (SPDT) consisting of a parallel diode (pin diode) (D1) (D2) or a transistor (Transistor).

According to another aspect, the RF switching circuit 200 is shown in Figure 5,

When a digital control signal is input to one bias port bias3, a transistor or a diode is turned on according to the level of the input digital control signal so that the GPS signal or the CDMA signal It is characterized by consisting of a single pole single throw (SPST) consisting of one diode (D3) for determining the flow.

Hereinafter, unexplained reference numerals L1 to L3 are coils, C1 to C6 are capacitors, and R1 to R5 are resistors.

Referring to Figures 3 to 5 attached to the embodiment of the present invention configured as described above are as follows.

First, when a GPS signal and a CDMA signal are received through the dual band antenna 100 having two frequency band characteristics, the dual band antenna 100 receives the received GPS signal and the CDMA signal from the RF switching circuit 200. Output to the input port.

In this case, the general digital input / output port (GPIO) of the modem chip 300 configured in the CDMA terminal applies a digital control signal of different patterns to the RF switching circuit 200,

The RF switching circuit 200 separates the GPS signal and the CDMA signal received from the dual band antenna 100 while switching on / off according to the applied digital control signal of the different patterns, and then the GPS signal. Is guided to the first antenna matching circuit 23, and the CDMA signal is led to the second antenna matching circuit 24.

That is, the RF switching circuit 200 has one input port connected to the dual band antenna 100 and the first and second antenna matching circuits 23 to have two output ports and parallel bias ports ( SPDT type consisting of bias1) (bias2) and diode D1 (D2) or transistor in parallel,

As shown in FIG. 4, a digital control signal having a different pattern is applied from a general-purpose digital input / output port (GPIO) of the modem chip 300 to a parallel bias port bias1 (bias2) configured in the RF switching circuit 200. .

Then, the parallel diodes D1, D2, or transistors configured in the RF switching circuit 200 are turned on in accordance with the level of the digital control signal input when the digital control signals having different patterns are input. Turn-on is made.

In addition, since the parallel circuits D1, C3, R1 (D2, C4, R2) by the Vg signal are turned on from the turn-on of the diode D1 (D2) or the transistor (Transistor), respectively.

The GPS signal and the CDMA signal are separated from the different conduction states of the parallel circuits D1, C3, and R1 (D2, C4, and R2), and the two signals are separated into the first and second antenna matching circuits 23 and 24, respectively. Through the output port of the flow can be guided.

Meanwhile, the RF switching circuit 200 may also be configured in the form of an SPST having one bias port bias3 and one diode D3 or transistor, as shown in FIG. 5.

As shown in FIG. 5, one digital control signal is applied from one general-purpose digital input / output port (GPIO) of the modem chip 300 to one bias port bias3 configured in the RF switching circuit 200.

Then, one diode D3 or transistor configured in the RF switching circuit 200 is turned on according to the level of the input digital control signal when the digital control signal is input. .

Then, conduction of the series circuits D3, C6, and R3 by the Vg signal occurs from the turn-on of the diode D3 or the transistor.

The GPS signal and the CDMA signal are separated from the conduction state of the serial circuits D3, C6, and R3, and the flow is guided through two output ports to the first and second antenna matching circuits 23 and 24, respectively. It will be possible.

Meanwhile, as another embodiment of the present invention, the input / output port of the RF switching circuit 200 may be extended according to additional devices (eg, Bluetooth, wireless LAN) added to the CDMA terminal. .

In addition, the RF switching circuit of FIGS. 4 and 5 does not use diodes D1, D2, and D3, and has a field effect transistor (FET) or a bipolar junction transistor (BJT: Bipolar) having an electrical on / off function. Junction Transistors can also be used, and the above circuit also applies to packaged switching ICs for RF. However, it is not necessarily limited to this.

As described above, in the present invention, since the terminal does not use the CDMA service when operating in the GPS mode, the dual-band antenna and the RF switching circuit are applied to the CDMA terminal, so that the GPS and CDMA signals can be separated and received more effectively. On the other hand, it prevents insertion loss when constructing CDMA terminal circuits in the band adjacent to the GPS band such as PCS, and eliminates the use of the internal antenna which is large in size and poor in mounting, thereby reducing the manufacturing cost of the terminal according to the circuit configuration. It provides the effect of reducing the difficulty of disposing parts in the terminal while saving.

Claims (6)

In a conventional CDMA terminal transceiver circuit, The dual-band antenna having two frequency band characteristics and the first and second antenna matching circuits for GPS and CDMA are applied to the transmission / reception circuit of the CDMA terminal. Between the dual band antenna and the first and second antenna matching circuits, the GPS signal received from the dual band antenna and the CDMA signal are separated and the GPS signal is guided to the first antenna matching circuit and the CDMA signal is the second antenna matching circuit. Configure an RF switching circuit with on / off switching with one input port and two output ports to guide to On / off switching of the RF switching circuit is controlled by a digital control signal output through a general-purpose digital input / output port of a modem chip according to GPS and CDMA communication modes. A CDMA signal separation receiver. The method of claim 1, wherein the RF switching circuit, SPDT (Single) consisting of parallel diodes to determine the flow of GPS signal and CDMA signal by turning on according to the level of digital control signal inputted when digital control signal of different pattern is input through parallel bias port. Pole double throw) GPS receiver and GPS receiver (CDMA) signal separation receiver of the mobile communication terminal characterized in that consisting of. The method of claim 1, wherein the RF switching circuit When a digital control signal is input to one bias port, it is composed of a single pole single throw (SPST) consisting of one diode that is turned on according to the level of the input digital control signal and determines the flow of the GPS signal or the CDMA signal. GPS and CDA (CDMA) signal separation receiver of a mobile communication terminal. The input and output port of the RF switching circuit, GPS and CDA signal receiving device of a mobile communication terminal, characterized in that the expansion is possible according to the additional device added to the CDA (CDMA) terminal. The RF switching circuit according to claim 2 or 3, GPS and CDA signal receiver of a mobile communication terminal, characterized by applying a field effect transistor (FET) having an electrical on / off function. The RF switching circuit according to claim 2 or 3, Switching circuit using Bipolar Junction Transistor (BJT) which has electrical on / off function, and RF IC of mobile communication terminal. CDMA) signal separation receiver.