JPH04281622A - Noise reduction system for radio communication equipment - Google Patents

Abstract

PURPOSE:To reduce noise of a transmission signal of the radio communication equipment and simultaneously to suppress the in-crease of product sized through the constitution by changing the frame frequency of a liquid crystal display. CONSTITUTION:The system is featured by providing a means in which after the depression of a transmission switch 2 is detected in a control unit 1, a control signal is sent to a transmission unit 5 and a liquid crystal display controller 3 and a frame frequency of the liquid crystal display is reduced to a degree not giving effect on the transmission signal, with a means which stops the transmission unit when the transmission switch 2 is released to activate a reception unit 6 and sends a control signal to restore the frame frequency of the liquid crystal display is restored and the frame frequency noise invaded in the transmission signal is reduced to avoid the increase of device size.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a noise reduction method for wireless communication equipment that enables clear information transmission and avoids increasing the size of the equipment by controlling the frame frequency of a liquid crystal. be.

0002

2. Description of the Related Art Conventionally, in order to reduce the noise of the frame frequency of a liquid crystal during transmission, as shown in FIG.
3 and inserting the shield plate 24 between the liquid crystal mounting board 21 and the transmitting unit board 25, and then connecting the liquid crystal mounting board 21 and the transmitting unit board 25 with the connection flexible cable 26 to reduce noise. I was shielding.

0003

[Problem to be solved by the invention] In this conventional method,
Depending on the positional relationship with other parts, the shield may be incomplete or may not be possible, and in order to complete the shield, space must be secured to install the shield plate, which may result in the product becoming larger. I had left it behind. In addition, methods other than those mentioned above include shortening the distance between the liquid crystal display section and the liquid crystal driver to reduce interference with other circuits. There were restrictions.

[0004] Normally, the frame frequency of a liquid crystal is 20
The frequency is about 0 to 300Hz (as a range where flickering is unlikely to occur), and the power supply voltage of the circuit is usually 5V, so the frame clock is also 5V P-P (Peak t
o Peak (the difference between the maximum and minimum values of the waveform), and the same applies hereafter), but as is well known, wireless communication devices are equipped with circuits that amplify minute electrical signals with high gain, and the above-mentioned As such, high-voltage alternating current signals of as high as 5V P-P are also generated and are exposed to conditions that are extremely susceptible to noise contamination. Furthermore, the audio passband of a communication device is usually 300 to 3000Hz, and the frame frequency mentioned above is near the lower limit of that, so if it were to enter the communication path, it would be within the audible range.
The quality of communication will deteriorate significantly.

Furthermore, if the frame frequency of the liquid crystal is set low (for example, about 60 Hz), it will be outside the audio passband of the communication device, so even if it were to be mixed in, it would be reduced by filters in both the transmitting and receiving systems. Although the quality of communication will not be affected, the displayed content may flicker when placed under lighting equipment or when the equipment is vibrated.

In the present invention, in order to compensate for these drawbacks, the frame frequency is set high (200 to 300 Hz) during reception, when the degree of noise contamination is relatively small, and there is a lot of work to operate the equipment and check the display. The frame frequency should be lowered (approximately 50 to 60 Hz) to maintain the quality of communication during transmission, where noise is likely to occur and the display is not looked at often, and the quality of the communication should be maintained. The challenge is to suppress the increase in the size of the equipment due to shielding and the addition of parts for that purpose.

[0007]

[Means for Solving the Problems] The noise reduction device for a wireless communication device of the present invention, when it is detected that the transmission switch is pressed in the control unit that adjusts the frame frequency of the liquid crystal, connects the transmission unit and the liquid crystal controller. A means for transmitting a control signal to reduce the frame frequency of the liquid crystal to a level that does not affect the transmitted signal, and a means for stopping the transmitting unit and operating the receiving unit when it is detected that the transmitting switch is released. At the same time, by providing means for sending a control signal that returns the frame frequency of the liquid crystal to its original value, frame frequency noise that sneaks into the transmitted signal is reduced, and the size of the product is avoided.

[0008]

[Embodiment] FIG. 1 shows an embodiment of the present invention, in which when the control unit 1 detects that the transmission switch 2 is pressed,
The receiving unit 6 is stopped by the signal c1. Then signal b
1 to operate the transmitting unit 5, and at the same time transmitting the signal a1 to the liquid crystal controller 3, the frame frequency of the liquid crystal display 4 is lowered to a level that does not affect the transmitted signal. This state is maintained until the control unit 1 detects that the transmission switch 2 is released. When it is detected that the transmitter switch 2 is released, the signal b2
The transmitting unit 5 is stopped with the signal c2, the receiving unit 6 is activated with the signal c2, and at the same time, the frame frequency of the liquid crystal is restored with the signal a2.

FIG. 3 is a flowchart showing the operation of the control unit 1. First, in step (S1), it is determined whether the transmission switch is in the ON state (pressed down) or the OFF state (released). If the transmission switch 1 is in the ON state, the control unit 1 sends a transmission a1 to the liquid crystal controller 3 in step (S2), thereby determining whether or not the change has been made. If the frame frequency has not been changed, the frame frequency is changed to one for transmission in step (S3), and if it has been changed or the frame frequency is changed to one for transmission in step (S3), the frame frequency is transmitted in step (S4). Processing is performed.

On the other hand, in step (S1), if the transmission switch is released and is in the OFF state, step (S1)
5), by sending the signal a2 from the control unit 1 to the liquid crystal controller 3, it is determined whether the frame frequency for reception has been changed. If the frame frequency has been changed or if the frame frequency is changed to one for reception in step (S6), reception processing is performed in step (S7). After receiving processing or sending processing,
The configuration is such that the process moves to step (S1) and the above-described operations can be repeated.

[0011]

[Effects of the Invention] As described above, the present invention enables clear information transmission by reducing the noise of transmitted signals, and at the same time eliminates the need for shield plates, etc., resulting in smaller products and easier assembly. It's easier and manufacturing costs are lower. Furthermore, by using a CPU with a built-in LCD driver, it is possible to configure the system using only software.

[Brief explanation of the drawing]

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

FIG. 2 is an embodiment for reducing noise in a conventional liquid crystal frame frequency.

FIG. 3 is a flowchart showing the operation of the control unit of the present invention.

[Explanation of symbols]

1 Control unit 2 Send button 3. LCD controller ４　　　　LCD DISPLAY 5 Transmission unit 6 Receiving unit 7. LCD mounting board 8　　　LCD 9 LCD mounting bracket 10 Shield plate 11 Transmission unit board

Claims (1)

[Claims] Claim 1: In a control unit that adjusts the frame frequency of a liquid crystal, when it is detected that a transmission switch is pressed, a control signal is sent to the transmission unit and a liquid crystal controller to adjust the frame frequency of the liquid crystal to a transmission signal. There is a means to reduce the frequency to a level that has no effect, and when it is detected that the transmitting switch has been released, the transmitting unit is stopped and the receiving unit is activated, while at the same time sending out a control signal that returns the frame frequency of the liquid crystal to its original value. 1. A noise reduction method for a wireless communication device, characterized in that it reduces frame frequency noise that wraps around a transmission signal and avoids increasing the size of the product.