JPH04219032A - Infrared ray receiver - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a remote control system between devices and an infrared receiving device used for information communication.

0002

2. Description of the Related Art In recent years, infrared rays have been increasingly used for remote control of electronic equipment and for simple information communication, and studies are underway to improve their reliability. The infrared receiving device has many opportunities for external noise to be mixed into the signal, so a reliable receiving function is required.

[0003] This type of infrared receiving device uses an infrared receiving unit. FIG. 3 shows a block diagram of a conventional infrared receiving device. In Figure 3, its constituent elements are 1
2 is an infrared receiving unit that receives infrared rays, and 2 is a microcomputer (hereinafter referred to as microcomputer).

Next, the related operations of the components of the above-mentioned conventional example will be explained. When receiving the sent infrared signal with an infrared receiving device, an infrared receiving unit is used to determine whether it is a logic 0 or logic 1, a leader (indicating the beginning of data), or a trailer (indicating the end of data). Convert the infrared signal sent by 1 into an electrical signal, input the converted signal to the input port of microcontroller 2,
Time T is set using a soft timer programmed by microcomputer 2.
and change the state L of the input port of microcontroller 2 every time T.
Or check H. For example, as shown in Fig. 4(a), the state of the input port is H for a time T and L for the next time T.
If so, it is determined to be logic 0, and if it is H for time T and L for the next time 3T, as shown in FIG. 4(b), it is determined to be logic 1. Regarding the leader and trailer, Fig. 4(c) and (d)
) is checked every time T, and the leader and trailer are determined according to the received code pattern shown in the figure.

[0005]

[Problems to be Solved by the Invention] However, in the above conventional configuration, since the time T is generated by a soft timer programmed in the microcomputer 2, the infrared receiving unit 1
The problem was that it was difficult to synchronize with changes in the output signal, the software became extremely complex, and it was easy to make erroneous judgments.

The present invention has been made in consideration of the above-mentioned problems, and an object of the present invention is to provide an infrared receiving device that can ensure synchronization with input signals and is free from misjudgment.

[0007]

[Means for Solving the Problems] In order to achieve the above object of the present invention, in an infrared receiving device having an infrared receiving unit that receives a signal by receiving infrared rays and outputs a digital signal, the digital signal as described above is provided. , a phase comparator for comparing the phases of the digital signal and the clock signal, and a control means for detecting the rising or falling edge of the clock signal and detecting the level of the digital signal, The clock signal generated by this clock generating means is automatically phase-aligned with the digital signal by the output of the phase comparator.

[0008]

[Operation] The clock signal is synchronized with the digital signal from the infrared receiving unit by the phase comparator and the synchronization control means.
Since the phase alignment is automatically performed, the control means reads the edge of the clock signal and reads out the level of the digital signal at that phase, that is, H or L information. As a result, even if there is a frequency shift in the input signal or noise is mixed in, the readout position by the control means is the edge of the clock signal that is automatically and sequentially synchronized with the digital signal.
A reliable digital signal is read out. Further, the software in the special control means is not required, which simplifies the process.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of an infrared receiving apparatus showing an embodiment of the present invention. As shown in FIG. 1, the components include an infrared receiving unit 1 that receives infrared rays;
3 is a microcomputer, 3 is a phase comparison device that compares the electrical signal from the infrared receiving unit 1 with the clock from the voltage controlled oscillator (hereinafter referred to as VCO) 5, and outputs an error voltage; 4 is a phase comparison device that removes high-frequency components of the error voltage. low-pass filter (hereinafter referred to as L)
5 is a VCO whose frequency changes depending on the output level of the LPF.

Regarding the infrared receiving apparatus of the present invention constructed as described above, the related operations of its constituent elements will be explained below.

In order to determine logic 0 or logic 1, leader or trailer from the sent infrared signal, the infrared receiving unit 1 converts the sent infrared signal into a digital signal, and the converted signal is sent to the first microcomputer 2. The phase comparator 3 compares the phases of the electrical signal and the clock signal output from the VCO 5 to generate an error voltage, and the LPF 4 extracts the high-frequency components of the error voltage. is removed, the voltage is input to the VCO 5, and a clock signal is generated while changing the frequency depending on the voltage level. By connecting the generated clock signal to the phase comparator 3, a so-called PLL whose phase is automatically adjusted is formed, and the VCO 5 generates the clock signal in synchronization with the electrical signal converted by the light receiving unit 1. The output of the VCO 5 is input to the second input port 7 of the microcomputer 2. The microcomputer 2 to which these inputs have been made functions as a control means to detect the falling and rising edges of the clock signal, and after detection, confirms the state L or H of the electrical signal. For example, as shown in Fig. 2(a), if the state of the port inputting the electrical signal is H for time T and L for the next time T, it is determined to be logic 0, and as shown in Fig. 2(b), time T
If it is H only for the next time and L for the next time 3T, it is determined to be logic 1. Although not shown, the leader and trailer are also checked at time T, and depending on the pattern, the leader and trailer are checked.
Judge the trailer. When no infrared signal is sent, the VCO 5 generates a clock at a free-run frequency of 1/(2T). When the infrared signal is sent, the VCO 5 generates a clock signal at a frequency of 1/(2T) in synchronization with the output data of the infrared receiving unit 1. In this way, since the clock signal is always synchronized with the input digital signal, the information of the input digital signal can be reliably read.

[0013]

As is clear from the above description, the present invention provides a means for generating a clock signal synchronized with an input digital signal, thereby reducing the time required to determine data read timing by a program in a control means such as a microcomputer. There is no need for a soft timer, the software can be simplified, and furthermore, due to the improved read timing accuracy, erroneous judgments can be prevented.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an infrared receiving device according to an embodiment of the present invention.

[Figure 2] (a) is a waveform diagram of the digital signal output from the infrared receiving unit of the same embodiment; (b) is a waveform diagram of the clock signal of the same embodiment;

[Figure 3] Block diagram of a conventional infrared receiving device

[Fig. 4] Waveform diagram for each reception code in the conventional infrared receiving device

[Explanation of symbols]

1 Infrared receiving unit 2 Microcomputer (control means) 3 Phase comparator

Claims (2)

[Claims] 1. An infrared receiving unit that receives a signal by receiving infrared rays and outputs a digital signal; a clock generating means that generates a clock signal that is synchronized with the digital signal output of the infrared receiving unit; and a phase comparator that compares the phases of the clock signal and a control means that detects a rising or falling edge of the clock signal and detects the level of the digital signal, and the output of the phase comparator is An infrared receiving device, wherein the clock signal is corrected to be synchronized with the digital signal by inputting the clock signal to a clock generating means. 2. The infrared receiving device according to claim 1, wherein the clock generating means is a voltage controlled oscillator.