KR100194760B1 - Receiver for wireless paging terminal that solves blanket area phenomenon - Google Patents

Abstract

The present invention relates to a receiver for a wireless paging terminal that solves the blanket area phenomenon in wireless communication, and further comprising a band pass filter in front of the high frequency amplifier of the wireless paging terminal to solve the blanket area phenomenon. To provide, a Korean mobile communication subscriber using a receiving apparatus further comprising a first band pass filter 31 for receiving a radio call signal received through an antenna and passing a first predetermined frequency band, It is possible to receive the wireless calling service without being affected by the frequency of the wireless calling second operator near the wireless calling second operator base station, and the reception rate of the Korean mobile subscriber station is within 20m within the radius of the wireless calling second operator base station. In a situation of low or less than% or a wireless calling terminal using the present invention There is an effect that can greatly improve the radio call reception rate in the vicinity of the radio call second operator base station to more than 90%.

Description

Receiver for wireless paging terminal that solves blanket area phenomenon

1 is an exemplary configuration diagram of a general wireless paging terminal.

2 is a configuration diagram of a receiver of a conventional radio calling terminal.

3 is a block diagram of an apparatus for receiving a radio calling terminal according to an embodiment of the present invention.

* Explanation of symbols for main parts of the drawings

31, 33, 35: surface acoustic wave filter 32: high frequency amplifier

34, 36 mixer 37, 38 local oscillator

The present invention relates to a receiver for a radio calling terminal that solves the blanket area phenomenon in wireless communication.

The wireless paging service has been rapidly developed since the Korean mobile communication service began in 1984, and this trend has been accelerated by the emergence of the wireless paging second service provider.

However, serious problems in service have occurred between Korea's mobile telecommunication service and wireless call second service providers since the wireless call second service provider started. Among them, a blanket area in which the wireless call reception rate rapidly decreases around a base station is common. (Blanket Area) Phenomenon.

The radio call blanket area phenomenon refers to a phenomenon in which a reception rate decreases due to interference of a weak reception force by a strong force due to mutual signal interference between a Korean mobile communication service and a second radio call operator around a radio call base station.

Currently, domestic wireless paging service providers use two bands, 160MHz band and 320MHz band. Since 160MHz band is used by Korean mobile communication alone, no blanket area phenomenon occurs. As the mobile communication and the wireless paging second service providers share the frequency, a blanket area phenomenon occurs around the base station.

In order to solve the radio call blanket area, first, the Ministry of Information and Communication allocates frequencies without mutual interference by providing sufficient frequency separation distance between the Korea Mobile Communication and the 2nd Call Operators. There is a way for operators to use a common base station. However, the two approaches mentioned above are expected to be quite difficult.

Accordingly, an object of the present invention is to provide a receiver for a radio calling terminal, which further includes a band pass filter in front of the high frequency amplifier of the radio calling terminal, thereby solving the blanket area phenomenon.

In order to achieve the above object, the present invention comprises: a first band pass filtering means for receiving a radio signal received through an antenna and passing a first predetermined frequency band; High frequency amplifying means for receiving an output of the first band pass filtering means and amplifying a gain while suppressing noise of a high frequency signal; First local oscillating means for generating a first reference signal; First frequency mixing means for mixing the output of the high frequency amplifying means and the first reference signal of the first local oscillating means to output a first intermediate frequency; Second band pass filtering means for receiving a first intermediate frequency of the first frequency mixing means and passing a second predetermined frequency band; Second local oscillating means for generating a second reference signal; And second frequency mixing means for mixing the output of the second band pass filtering means and the second reference signal of the second local transmission means to output a second intermediate frequency to an external decoding means. .

Hereinafter, with reference to the accompanying drawings will be described an embodiment according to the present invention;

1 is a configuration diagram of a general wireless paging terminal, where 11 is a receiver, 12 is a decoder, 13 is a data processor, and 15 is a display.

The structure of a radio call terminal corresponding to a terminal equipment of a radio call system generally includes a receiver 11 for demodulating a radio call data transmission code (POCSAG CODE) by receiving radio waves emitted into the air through a radio call exchanger and a base station, and demodulation. A decoder (DECODER) 12 for recovering the desired information data from the signal. And a data processing unit 13 for converting the decoded signal into a message and a display unit (LCD) 14 for displaying the converted message for the subscriber to see.

The receiver 11 reduces the influence of the image frequency by using a known homodyne or zero-IF technique, and uses a direct conversion reception technique for convenience of manufacturing. In some cases, commercially available wireless paging terminals currently use a double conversion reception technique in consideration of high sensitivity and low power consumption.

2 is a block diagram of a receiver of a wireless paging terminal using a conventional double conversion reception scheme, in which 21 is a high frequency amplifier, 22 and 24 are surface elasticity and filters, 23 and 25 are mixers, and 26 is the first order. Local oscillator, 27 represents a secondary local oscillator, respectively.

In general, the ultra-short configuration of most radio frequency (RF) receiving terminals includes a high frequency amplifier, a bandpass filter, a mixer, and a demodulator.

The intermediate frequencies IF of the mixers 23 and 25 use 10.7 MHz or 21.4 MHz and generate 455 kHz as the secondary intermediate frequency.

The high frequency amplifier 21 serves to increase the gain while suppressing noise of the high frequency signal directly introduced from the antenna. In general, a low noise amplifier (LNA) is used directly behind the antenna to increase receiver sensitivity.

The elastic surface (SAW) filter 22 is used as a band pass filter. The elastic surface and the characteristics of the filter 22 are most commonly used in radio calling terminals at home and abroad because they are suitable for mass production because they are smaller, lighter than dielectric filters, and are manufactured by the same photolithography as integrated circuit (IC) fabrication. It is used.

Mixers 23 and 25 mix the received signal with reference signals generated from primary and secondary local oscillators 26 and 27 and transition to intermediate frequencies of 20.4 MHz and 455 kHz, respectively.

The part after the receiving device was viewed by the decoder 13, demodulated in a ROM code of the terminal, which identifies its own signal among the numerous signals emitted by the base station equipment, and then given to the ROM of the terminal. If it matches the code, it decodes the message data that follows and passes the information to the central processing unit (CPU). The central processing unit (CPU) provides a display of received information and an alarm to a subscriber, and performs various additional functions according to the processing of software.

3 is a block diagram of a receiving apparatus of a wireless paging terminal according to an embodiment of the present invention, 31, 33 and 35 are surface acoustic wave filters, 32 are high-frequency amplifiers, 34 and 36 are mixers, 37 is a primary local oscillator, 38 represents the secondary local oscillator, respectively.

The present invention adds a surface acoustic wave filter (SAW FILTER) 31 between the antenna of the radio call terminal and the high frequency amplifier 32 of the receiver to operate as a band pass filter, so that it occurs in the high frequency amplifier 32 of the receiver. By suppressing intermodulation as much as possible, only one of the signals of the Korean mobile communication service or the second wireless call service was received.

Intermodulation is a phenomenon in which a new frequency is generated by a combination of input frequencies when a radio wave is input to a circuit having a nonlinearity such as an amplifier. It is a kind of noise and interference of a reception system.

As an application example of the present invention as described above, the surface acoustic wave filter 33 connected directly to the rear end of the high frequency amplifier 32 is used instead of the surface elasticity and the filter 31 added to the front end of the high frequency amplifier 32. The same operation effect can be obtained even when it is removed.

In addition, as another application example of the present invention, even in a wireless paging terminal using a known homodyne technique, the same operation effect can be obtained by newly adding the surface acoustic wave filter 31 to the front end of the high frequency amplifier. Here, the homodyne technique is a carrier suppression transmission scheme in which one or both sidebands of a sideband is transmitted without transmitting a carrier component of a modulated wave. The homogeneous scheme reproduces a reference carrier at a transmitter by a local oscillator to demodulate at a receiver. It is a way to mix this with the transmission signal.

As a result of measuring the terminal reception rate by selecting a few base stations with the most blanket area phenomenon, it is found that the reception rate of the conventional mobile telecommunication terminal in Korea is very poor within the radius of 300m of the base station. Could know.

However, as in the present invention, the reception device of the wireless call terminal is reconfigured to add a surface acoustic wave filter (31) directly to the rear end of the antenna to be transmitted to the high frequency amplifier (32). It was confirmed that the improvement over%.

This is because only the Korean mobile communication frequency band (327.XXX to 328.XXX MHz) is passed through the surface acoustic wave filter (SAW Filter) 31 added immediately behind the antenna of the wireless paging terminal, and then the high frequency amplifier 32 and the mixer ( 34, 36) to form a radio frequency (RF) to reduce the effects of inter-modulation occurring inside the radio calling terminal.

As described above, the present invention enables a Korean mobile communication subscriber to be provided with a wireless calling service without being influenced by the frequency of the wireless calling second operator around the wireless calling second operator base station. Within the situation that the reception rate of the Korean mobile communication subscriber terminal is less than 20% or less, the wireless call terminal using the present invention can greatly improve the wireless call reception rate around 90% of the wireless call second operator base station. .

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 apparent to those of ordinary skill.

Claims (4)

A receiving apparatus of a radio calling terminal, comprising: band pass filtering means for directly receiving a radio call signal received through an antenna and passing a predetermined frequency band; And receiving means for suppressing and receiving the intermodulation of the signal passing through the band pass filtering means. The reception device according to claim 1, wherein the band pass filtering means is a surface acoustic wave (SAW) filter. A receiving apparatus of a radio calling terminal, comprising: first band pass filtering means for receiving a radio signal received through an antenna and passing a first predetermined frequency band; High frequency amplifying means for receiving an output of the first band pass filtering means and amplifying a gain while suppressing noise of a high frequency signal; First local oscillating means for generating a first reference signal; First frequency mixing means for outputting a first intermediate frequency by mixing the output of the high frequency amplifying means and the first reference signal of the first local oscillating means; Second band pass filtering means for receiving a first intermediate frequency of the first frequency mixing means and passing a second predetermined frequency band; Second local oscillating means for generating a second reference signal; And second frequency mixing means for mixing the output of the second band pass filtering means and the second reference signal of the second local transmission means to output a second intermediate frequency to an external decoding means. Receiving device. 4. The receiver of claim 3, further comprising: third band pass filtering means for receiving an output of the high frequency amplifying means and passing a third predetermined frequency band to the first frequency mixing means.