KR20040110310A - Transmitting apparatus in Dual band Wireless Telecommunication Terminal - Google Patents

Abstract

PURPOSE: A transmitting device in a wireless communication terminal for a dual band is provided to more efficiently remove noises of a cellular frequency band signal and a PCS(Personal Communication Service) frequency band signal outputted from a signal generator by using two diplexers instead of two SAW(Surface Acoustic Wave) filters. CONSTITUTION: A signal generating unit(21) generates a signal of a PCS frequency band and a signal of a cellular frequency band according to a communication frequency band. The first diplexer(22) removes noise from the signals of the PCS frequency band and the cellular frequency band generated from the signal generating unit(21). The second diplexer(23) divides the signals outputted from the first diplexer(22) according to each frequency band. Amplifying units(24,25) amplify the signal of the cellular frequency band and the signal of the PCS frequency band divided by the second diplexer(23). A coupler(26) isolates the signal of the cellular frequency band with the signal of the PCS frequency band to prevent interference between the signals. The first duplexer(27) and the second duplexer(28) separate a transmitting signal and a receiving signal from the signal of the cellular frequency band and the signal of the PCS frequency band. The third diplexer(29) divides the signals of the cellular frequency band and the signal of the PCS frequency band, and transmits an output signal corresponding to each frequency band through an antenna.

Description

Transmitting apparatus in Dual band Wireless Telecommunication Terminal

The present invention relates to a transmission apparatus of a dual band wireless communication terminal, and more particularly, to a transmission apparatus of a wireless communication terminal for transmitting a signal through a cellular frequency band or a PCS frequency band.

In the present invention, the wireless communication terminal is a mobile communication terminal, a personal communication service (PCS) terminal, a personal digital assistant (PDA), a smart phone, a next generation mobile communication (IMT-2000) terminal, a wireless LAN terminal, and the like through wireless communication, Refers to a portable wireless communication terminal capable of transmitting and receiving text and image data.

For better understanding, a transmission apparatus of a conventional dual band wireless communication terminal will be described with reference to FIG. 1.

As shown in FIG. 1, a conventional dual band wireless communication terminal transmitting apparatus includes: a signal generator (RFT) 11 for generating a signal of a cellular frequency band or a signal of a PCS frequency band according to a communication frequency band; A first surface acoustic wave filter (SAW) 12 for removing noise from a signal of the cellular frequency band output from the signal generator 11, and noise from a signal of the PCS frequency band output from the signal generator 11. A second surface acoustic wave filter (13) for removing a signal, a first amplifier (PAM) 14 for amplifying a signal in a cellular frequency band from which noise is removed from the first surface acoustic wave filter (12), and 2 the second amplifier 15 for amplifying the signal of the PCS frequency band from which the noise is removed from the surface acoustic wave filter 13, the signal of the cellular frequency band amplified by the first amplifier 14, and the second amplifier 15 Increase A coupler 16 for isolating the signals of the PCS frequency band from each other, a first duplexer 17 for separating the transmission signal and the received signal from the signal of the cellular frequency band, and the PCS frequency band And a second duplexer 18 for separating a transmission signal and a reception signal from a signal of a signal, and a diplexer 19 for separating a transmission / reception signal of a cellular frequency band and a signal of a PCS frequency band.

Here, the duplexers 17 and 18 and the diplexer 19 will be described in more detail. The duplexers 17 and 18 strictly distinguish between the transmitted signal and the received signal in the cellular signal and the PCS signal which do not have a large frequency band difference. Therefore, the bandpass filter (BPF) for transmission signal and the reception signal bandpass filter (BPF) have good filtering performance, while the diplexer 19 separates two signals (cellular signal, PCS signal) having a large frequency band difference. Therefore, it consists of a low pass filter (LPF) and a high pass filter (HPF), which is relatively poor in filtering performance.

On the other hand, the frequency band of the first surface acoustic wave filter 12 that removes noise from the cellular frequency band signal is 824 MHz to 850 MHz, and the frequency band of the second surface acoustic wave filter 13 that removes noise from the signal of the PCS frequency band. Is 1850 MHz to 1910 MHz.

Here, the characteristics of the surface acoustic wave filters 12 and 13 will be described in more detail. The insertion loss is generally 2.5 decibels and the attenuation is generally 35 to 40 dB.

In the frequency bands of the first duplexer 17 and the second duplexer 18, the received signals are 1930 MHz to 1980 MHz, and the transmitted signals are 1850 MHz to 1910 MHz.

In addition, the diplexer 19 includes both cellular frequency bands (820MHz to 900MHz) and PCS frequency bands (1850MHz to 1980MHz).

Such a conventional dual band wireless communication terminal transmission apparatus uses an expensive surface acoustic wave filter (SAW) with poor performance, thereby lowering the transmission performance of the wireless communication terminal and increasing the price of the terminal. There was also a problem of increasing the size.

The present invention has been proposed to solve the above problems. Unlike the conventional method in which two surface acoustic wave filters are used to reduce noise of the cellular frequency band signal and the PCS frequency band signal output from the signal generator, two diples are provided. It is an object of the present invention to provide a transmission apparatus of a dual band wireless communication terminal for more efficiently removing noise using a lexer.

1 is a block diagram of a transmission apparatus of a conventional dual band wireless communication terminal.

2 is a block diagram of an embodiment of a transmission apparatus of a dual band wireless communication terminal according to the present invention;

3 is a configuration diagram of another embodiment of a transmission device for a dual band wireless communication terminal according to the present invention;

Figure 4 is a configuration of another embodiment of a transmission device for a dual band wireless communication terminal according to the present invention.

5 is a configuration diagram of yet another embodiment of a transmission device for a dual band wireless communication terminal according to the present invention;

* Explanation of symbols for the main parts of the drawings

21: signal generator 22: first diplexer

23: second diplexer 24: first amplifier

25 second amplifier 26 coupler

27: first duplexer 28: second duplexer

29: third diplexer

An apparatus of the present invention for achieving the above object is characterized in that it comprises a.

The above objects, features and advantages will become more apparent from the following detailed description taken in conjunction with the accompanying drawings. Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The transmission apparatus of the dual band wireless communication terminal according to the present invention will be described with reference to FIGS. 2 to 5 as follows.

As shown in FIG. 2, the apparatus for transmitting a dual band wireless communication terminal according to the present invention includes a signal generator (RFT) 21 for generating a signal of a cellular frequency band or a signal of a PCS frequency band according to a communication frequency band. ), A signal output from the first diplexer 22 and a signal output from the first diplexer 22 for removing noise from the signal of the cellular frequency band and the signal of the cellular frequency band output from the signal generator 21. A second diplexer 23 for transferring to the first amplifier 24 in the case of a signal of the cellular frequency band and to the second amplifier 25 in the case of a signal of the PCS frequency band according to the frequency band of A first amplifier 24 for amplifying the signal in the cellular frequency band received from the second diplexer 23, a second amplification for amplifying the signal in the PCS frequency band received from the second diplexer 23; 25, a coupler 26 for isolating the signal of the cellular frequency band amplified by the first amplifier 24 and the signal of the PCS frequency band amplified by the second amplifier 25 from interfering with each other. ), A first duplexer 27 for separating a transmission signal and a reception signal from a signal of a cellular frequency band, a second duplexer 28 for separating the transmission signal and a reception signal from a signal of a PCS frequency band, And a third diplexer 29 for separating the signal from the signal in the PCS frequency band.

Here, the first amplifier 24 and the second amplifier 25 may be implemented as one dual PAM, as shown in FIG. 3.

In addition, the second diplexer 23 is configured as the matching circuit 43 as shown in FIG. 4.

In addition, although the first amplifier 44 and the second amplifier 45 are separately implemented in FIG. 4, as shown in FIG. 5, one dual amplifier may be implemented.

Meanwhile, the first diplexers of FIGS. 2, 3, 4, and 5 may filter cellular frequency bands (824MHz to 850MHz) and PCS frequency bands (1850MHz to 1950MHz), and insertion loss (Insertion Loss) Typically 0.5dB and attenuation typically 20dB.

Here, as an example of the signal generator (shown in FIGS. 2 to 5), the RF6100 (hereinafter referred to as "RFT6100") will be described. The current RFT6100 level is 8 dBm (mW). Unit power in dB scale) to (-80 dBm), PCS output power from 10 dBm to (-78 dBm), and carrier Suppression Celluar Tx Passband Out Power up to -48 dBc ( Ratio of the sideband power to the total power in the signal band), at least -17 dBc, and the carrier transmission PCS Tx Passband Out Power has a maximum of -50 dBc, at least -19 dBc. In addition, the inverse attenuation of the cellular signal (Image Suppression Celluar) is -42 dBc and the inverse attenuation of the PCS signal is -19 dBc.

Therefore, considering that the input level of the band pass filter (BPF) input terminal is -5 dBm to -10 dBm, it can be seen that the RFT6100 has an appropriate output level.

In addition, in one embodiment of the present invention, the signal of the cellular frequency band and the signal of the PCS frequency band have been described as an example, but other frequency bands may be implemented.

In addition, the present invention may be used not only for a dual band wireless communication terminal but also for a tri band wireless communication terminal.

The present invention described above is not limited to the above-described embodiments and the accompanying drawings, and various substitutions, modifications, and changes are possible in the art without departing from the technical spirit of the present invention. It will be clear to those of ordinary knowledge.

The present invention as described above, by using a low-cost diplexer in the transmission device of the dual-band wireless communication terminal more efficiently to remove noise, it has the effect of lowering the price of the dual-band wireless communication terminal.

In addition, the present invention can obtain a gain of about 2dB using a diplexer, it is possible to reduce the size of the dual-band wireless communication terminal.

Claims (3)

In the transmitting device of a dual band wireless communication terminal, Signal generating means for generating a signal of a cellular frequency band or a signal of a PCS frequency band in accordance with a communication frequency band; First diplexing means for removing noise from a signal of a cellular frequency band and a signal of a PCS frequency band output from said signal generating means; Second diplexing means for separating signals output from the first diplexing means according to frequency bands, respectively; Amplifying means for amplifying a signal of a cellular frequency band and a signal of a PCS frequency band separated by said second diplexing means; Coupling means for isolating a signal of the cellular frequency band amplified by the amplifying means from a signal of the PCS frequency band from interfering with each other; First and second duplexing means for separating the transmission signal and the reception signal from the signal of the cellular frequency band and the signal of the PCS frequency band, respectively; And Third diplexing means for separating the received cellular frequency band signal from the PCS frequency band signal and transmitting the signal through an antenna as an output signal for each frequency band; Transmission device of a dual band wireless communication terminal comprising a. The method of claim 1, The amplification means, A transmission apparatus of a dual band wireless communication terminal, characterized in that the dual amplification means. The method according to claim 1 or 2, The second diplexing means, And a matching circuit for matching impedance and separating signals according to frequency bands.