JP2000114999A - Radio data communication equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the S/N of place weak in a radio wave level from a base station by storing the noise levels of plural bands, inputting the intensity of a received electric field from a radio communication unit, comparing the intensities of two fields and on/off-controlling the spectrum spread function in a clock generation means in accordance with the result. SOLUTION: A noise level radiated from a PC main body is measured in a state where a portable telephone 2 is not previously connected. The level of noise is stored in a storage part 14 at every radio communication channel. At the time of executing radio data communication, the intensity of the received electric field of a radio wave from the base station of the radio channel which is to be used is obtained from the portable telephone 2 through a portable telephone interface part 16. The noise level which the PC main body radiates in a frequency applied to the radio channel when a spectrum spread part is turned off is compared with the obtained intensity of the received electric field of the radio channel by a comparator 15. Thus, a spectrum spread control part 13 executes spectrum spread by the result.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a data processing device,
In particular, in a wireless data communication apparatus for performing data communication by connecting a wireless communication device and a personal computer, a function of suppressing noise generated from the personal computer is provided.

[0002]

2. Description of the Related Art When a personal computer (PC) is carried and used by connecting to a network, PCMCI is used.
Data communication is performed by connecting to a wireless communication device such as a mobile phone via the A interface card. In such a wireless data communication device, in a situation where the strength of the electric field used for communication is distant from the base station, the noise radiated by the PC main unit affects the signal of the wireless communication and degrades the S / N ratio. In some cases, wireless data communication cannot be performed. In order to perform wireless data communication stably, a mechanism for reducing noise radiated by the PC body is required. For example, as disclosed in JP-A-9-98152, FIG.
FIG. 2 shows a spectrum of noise caused by applying FM modulation to a clock having a spectrum as shown in FIG.
As shown in (b), the peak of noise generated by the PC main body is reduced by diffusion. As a result, an attempt is made to enable high-quality wireless data communication by reducing the influence of noise generated by the PC main body on wireless communication devices. As shown in FIG. 2, the spectrum of the clock harmonic noise generated by the clock of the PC is spread over a wide band to reduce the peak value of the noise.

[0003]

However, in the conventional example, the peak level is reduced in order to reduce the peak level by spreading the noise spectrum, but the noise is spread over the entire band. Therefore, in a state where only a specific communication channel is buried in noise as shown in FIG. 3A, the noise is spread over many communication channels as shown in FIG. 3B. Therefore, almost all communication channels are blocked by noise, and there is a problem that the spread of the spectrum may make communication impossible.

[0004] In view of the above, the present invention controls whether or not to spread the spectrum of the clock of the main unit based on the received electric field strength of the communication channel used from the connected wireless communication device, thereby reducing the radio wave level from the base station. The purpose is to improve the S / N ratio in a weak place.

[0005]

SUMMARY OF THE INVENTION The present invention provides a clock generating means having a spread spectrum function, a means for storing noise levels in a plurality of bands, a means for inputting a received electric field strength from a radio communication device, and the input means. Means for comparing the intensity between the means and the storage means, and control means for controlling on / off of the spread spectrum function of the clock generation means based on the comparison result of the comparison means. A wireless data communication device having a function of suppressing.

Accordingly, even in a place where the radio wave level is weak,
A wireless data communication device capable of performing stable communication is obtained.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention comprises a clock generation unit having a spread spectrum function, a storage unit for storing noise levels in a plurality of communication channels, and a communication channel for receiving from a wireless communication device. An interface unit for inputting an electric field intensity, a comparing unit for comparing the electric field intensity between the input unit and the storage unit, and controlling ON / OFF of a spread spectrum function of the clock generating unit based on a comparison result of the comparing unit. And a control unit for controlling on / off of a spread spectrum function so as to improve an S / N ratio of a communication channel used in wireless communication. Even when the level is weak, the S / N ratio between the noise generated by the PC and the electric field strength of the communication channel is optimally selected. A.

(Embodiment) FIG. 1 is a block diagram of a wireless data communication apparatus according to an embodiment of the present invention. 1 is a personal computer (PC), 2 is a mobile phone, 11
Is a clock generation unit that supplies a clock to each unit of the PC, 1
2 is a built-in clock generation unit 11 for spreading a clock spectrum, 13 is a spread spectrum control unit, and 14 stores a noise level radiated by the PC main body in a state where the spread spectrum is turned off for each radio channel. Is a comparator, 15 is a comparator, and 16 is a mobile phone interface unit. In this embodiment, it is assumed that the peak level of noise can be reduced by 10 dBμ by turning on the spread spectrum function. When the spread spectrum function is on, the spectrum is spread over 1 MHz.

The operation of the wireless data communication apparatus according to the present embodiment configured as described above will be described below.

In the present embodiment, the noise level radiated from the PC main body is measured in advance without connecting the mobile phone 2, and the level of the noise radiated by the PC main body for each wireless communication channel is stored in the storage unit 14. It is stored (FIG. 4). When performing wireless data communication, the mobile phone 2 obtains, via the mobile phone interface unit 16, the received electric field strength of the radio wave from the base station of the wireless channel to be used. The comparator 15 compares the noise level radiated by the PC main unit at the frequency corresponding to the wireless channel and the obtained reception electric field strength of the wireless channel when the spread spectrum unit is turned off, which is stored in the storage unit 14. Compare.

The spread spectrum controller 13 includes a comparator 15
As a result, when the received electric field strength is higher than the stored PC noise level, the spectrum spreading section 12 is turned on to perform spectrum spreading. When the received electric field strength is equal to or lower than the stored PC noise level, the spectrum spreading section is turned off and spectrum spreading is not performed. That is, when the received electric field strength of the wireless channel to be used is higher than the PC noise level, the S / N is increased by lowering the peak level of the noise by the spread spectrum function, and the communication quality is improved.

For example, in order to use the communication channel 3, the reception electric field strength is obtained from the mobile phone 2. As shown in FIG. 5A, assuming that the received electric field strength is higher than the noise level and is 40 dBμ, the noise is 20 dBμ when the spread spectrum function is off, so the S / N ratio is 20 dB. Turning on the spread spectrum function reduces noise by 10 dBμ, so that the S / N ratio can be increased to 30 dB as shown in FIG. 5B.

On the other hand, when the received electric field strength of the radio channel to be used is equal to or lower than the PC noise level, the spectrum is not spread. For example, as shown in FIG. 6A, when the received electric field strength obtained from the mobile phone 2 is 10 dBμ when the communication channel 3 is used, when the spread spectrum function is turned on, the noise level of the communication channel 3 becomes 1
However, as shown in FIG. 6 (b), noise of 10 dBμ spreads over all communication channels due to spread of the spectrum, and noise corresponding to the radio field intensity from the base station is generated. Will be. At this time, the spread spectrum function is turned off, and the mobile phone 2 is instructed to change the wireless communication channel through the mobile phone interface 16. here,
It is instructed to switch to another communication channel with a low noise level, for example, CH1. In other words, if spread spectrum is performed when the reception electric field strength of the wireless channel to be used is equal to or lower than the PC noise level, a channel that can be used by spreading noise not only to the wireless channel but also to a plurality of wireless channels due to the spread of the noise spectrum. Decreases or disappears. Rather than reducing the number of usable wireless channels, a choice is made to use another wireless channel free of PC noise even if the reception strength is low.

As described above, according to the present embodiment, the spectrum spread of the clock is performed by comparing the received electric field strength obtained from the connected radio equipment with the level of the main body noise for each radio communication channel stored in advance. By controlling whether or not the wireless data communication apparatus can communicate even in a place where the radio wave level from the base station is weak, a wireless data communication apparatus can be provided.

Although a mobile phone is used as a wireless communication device in the present embodiment, it is obvious that a similar function can be realized by using another wireless communication method such as PHS.

[0016]

As described above, according to the present invention,
By controlling whether or not to spread the clock spectrum, it is possible to avoid the influence of noise on the wireless channel regardless of whether the radio wave intensity from the base station is strong or weak, and to achieve good wireless data communication. Therefore, the practical effect is great.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of the present invention.

2A is a spectrum diagram of noise generated by a PC when spread spectrum is off; FIG. 2B is a spectrum diagram of noise generated by a PC when spread spectrum is on;

FIG. 3 is a diagram showing that the signal is blocked by spread spectrum. (A) Spectrum diagram of noise covering a communication channel when spread spectrum is off. (B) Spectrum of noise covering a communication channel when spread spectrum is on. Figure

FIG. 4 is a diagram showing a noise level for each communication channel.

FIG. 5A is a diagram showing a noise margin when the spread spectrum is turned off when the received electric field intensity is higher than the noise level. FIG. 5B is a diagram showing the noise margin when the received electric field intensity is higher than the noise level.
Diagram showing noise margin with spread spectrum on

6A is a diagram illustrating a noise margin when the spread spectrum is turned off when the received electric field intensity is lower than the noise level. FIG. 6B is a diagram illustrating the noise margin when the received electric field intensity is lower than the noise level.
Diagram showing noise margin with spread spectrum on

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 PC 2 Mobile telephone 11 Clock generation part 12 Spread spectrum part 13 Spread spectrum control part 14 Storage part 15 Comparator 16 Mobile telephone I / F

Claims (1)

[Claims] 1. A clock generation unit having a spread spectrum function, a storage unit for storing noise levels in a plurality of communication channels, an interface unit for inputting an electric field strength of a communication channel received from a wireless communication device, and the input unit Comparing means for comparing the electric field strength of the storage unit and
A control unit for controlling ON / OFF of a spread spectrum function of the clock generation unit based on a comparison result of the comparison unit, and
/ Spread spectrum function on to improve / N ratio /
A wireless data communication device, which is turned off.