JPH11187075A - Infrared reception equipment and signal processing method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide infrared reception equipment and a signal processing method therefor with which probability of the occurrence of communication errors or the like is decreased by transforming to a signal in any possible form an electric signal which is turned into a normally unrealizable form without being converted to a signal with a pulse width determined at the time of photoelectric conversion of an optical pulse in infrared communication. SOLUTION: This equipment has a photoelectric converting part 11 for converting an optical signal of received infrared rays to an electric signal, a filtering part 12 for transforming the electric signal into a determined pattern when the electric signal photoelectric-converted by the converting part 11 is not compatible with the determined pattern, and a decoder 13 for recognizing received data by analyzing the format determined by IrDA standards.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an infrared receiving apparatus and a signal processing method in the infrared receiving apparatus. More specifically, for example, when performing 4 Mbps communication of IrDA communication, an optical pulse is converted into an electric pulse signal to convert data into data. The present invention relates to an infrared receiving device having a filter for correctly receiving data when receiving the data, and a signal processing method in the infrared receiving device.

[0002]

2. Description of the Related Art Conventionally, in the IrDA high-speed communication mode, communication can be performed at a speed of 4 Mbps. However, transmission and reception waveforms are determined by standards, and are determined to be performed by the 4PPM method. FIG. 7 is a diagram showing a correlation between a data pulse and data in the method. Each received pulse has 2 bits of information depending on the position, and
The interval of 0 ns is divided into four intervals of 125 ns, and data is represented by the locations. (1) to (4) indicate information of 00, 01, 10, and 11, respectively. When information (5) is received (00 after 11), the fourth pulse and the first pulse are received, so that the pulse width is twice as large as the normal pulse width. This is called a double pulse. A normal received signal is called a single pulse to distinguish it from a double pulse. The double pulse does not exist unless the above information is received.

[0003] The IrDA standard specifies that communication be performed in frame units. FIG. 8 is a diagram showing a frame of the IrDA standard. The frame of the IrDA standard includes a preamble, a start flag, an address field, a control field, a data field,
FCS and stop flag. The detailed description of the frame is omitted because it is defined by the IrDA standard. However, in the preamble, start flag, and stop flag areas, the above-mentioned double pulse does not exist.

[0004] In an infrared communication device, after receiving an optical pulse having the above-described form, the optical pulse is usually converted into an electric pulse signal by a photoelectric conversion unit to handle data. When these data are received, 2M
When receiving a signal of 4PPM of a signal of 8 Hz, 8M
A sufficiently large frequency is required to receive a signal corresponding to Hz, and a reception clock synchronized with the received IrDA preamble signal is generated and reception is performed. However, by using this method, the signals coming into the clock of the entire system must be quite large, and if they are not needed throughout the system, The clock is prepared for communication, which is inefficient.

Conventionally, in photoelectric conversion, a photoelectric conversion element such as a pin photodiode is used, and its output is converted into a desired digital signal by using an amplifier or the like. In the present invention to be described later, a similar method is assumed in the photoelectric conversion unit, and the dynamic range of the arriving light is large, and the electric power of the width of the received light pulse is not necessarily determined based on the rising and falling speeds of the pin photodiode. It is assumed that a pulse signal cannot be obtained.

[0006]

By the way, the above-mentioned I
In the rDA standard, the light intensity of reception is also specified, but the dynamic range of received light is very large for infrared reception, and even if the same optical pulse signal is received, it is converted to an electric pulse signal. At present, it is very difficult to always output the pulse width with the same width as the light pulse. However, in decoding, since communication is performed using a 2 MHz 4PPM signal, it is necessary to accurately decode the pulse position and width of the signal.
In order to decode this correctly, an 8 MHz signal must be accurately recognized. For example, if sampling is not performed with a very fast clock of, for example, 48 MHz or more, there may be cases where accurate data cannot be recognized. There is.

[0007] However, in a printer engine mounted on an ink-jet printer or the like, a CPU or the like used for the printer engine does not use a clock that is so fast at present. Therefore, these devices are equipped with IrDA and FIR (Finite Impulse Re)
In order to realize sponse (finite impulse response) communication, a fast clock must be installed separately from the printer engine control unit only for FIR communication, which results in cost and radiation noise, and space for the board mounted on the device. At present, it is not efficient in terms of such factors.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described circumstances. In the case of infrared communication, when an electric signal is not converted into a pulse width determined at the time of photoelectric conversion of an optical pulse and becomes an impossible electric signal. It is another object of the present invention to provide an infrared receiving apparatus and a signal processing method in the infrared receiving apparatus that can reduce the probability of a communication error by converting the signal into a signal of a possible form.

[0009]

In order to achieve the above object, an invention according to claim 1 is an infrared receiving apparatus for receiving infrared light in a light pattern of a predetermined standard, wherein the infrared light signal is received by an electric signal. It is characterized by comprising photoelectric conversion means for converting the electric signal into a signal, and filter means for converting the electric signal into the pattern when the electric signal converted by the photoelectric conversion means does not correspond to the pattern.

In order to achieve the above object, the invention according to claim 2 is configured such that the filter means forms the pattern when an electric signal converted by the photoelectric conversion means has a pulse width longer than a specified pulse width. It is characterized by converting an electric signal into a signal.

In order to achieve the above object, the invention according to claim 3 is characterized in that the filter means, when sampling the electric signal converted by the photoelectric conversion means as a digital signal, at a frequency which is at least twice the transfer rate. The method is characterized in that sampling is performed, the sampling data is filtered, and an electric signal is converted so as to have the pattern.

In order to achieve the above object, the invention according to claim 4 is characterized in that the filter means converts the electric signal converted by the photoelectric conversion means into a signal which cannot be in the IrDA standard at the time of reception by IrDA standard 4 Mbps communication. In this case, the signal other than the signal corresponding to the pattern is filtered to obtain a possible electric signal.

In order to achieve the above object, the invention according to claim 5 is characterized in that it can be applied to an image forming apparatus such as a printer.

According to a sixth aspect of the present invention, there is provided a signal processing method in an infrared receiving apparatus for receiving infrared light in a light pattern of a predetermined standard, wherein the received infrared light signal is converted into an electric signal. The method includes a photoelectric conversion step of converting, and a filter step of converting an electric signal so as to become the pattern when the electric signal converted in the photoelectric conversion step does not correspond to the pattern.

In order to achieve the above object, the invention according to claim 7 is characterized in that, in the filter step, when the electric signal converted in the photoelectric conversion step has a pulse width longer than a specified pulse width, the pattern is formed. It is characterized by converting an electric signal into a signal.

In order to achieve the above object, the invention according to claim 8 is characterized in that in the filtering step, when the electric signal converted in the photoelectric conversion step is sampled as a digital signal, the frequency is twice or more as high as the transfer rate. The method is characterized in that sampling is performed, the sampling data is filtered, and an electric signal is converted so as to have the pattern.

In order to achieve the above object, the invention according to claim 9 is characterized in that in the filtering step, the IrDA standard of 4 Mb
When the electric signal converted in the photoelectric conversion step becomes a signal that cannot be in compliance with the IrDA standard at the time of reception by ps communication, the signal other than the signal corresponding to the pattern is filtered to be a possible electric signal. I do.

In order to achieve the above object, the invention according to claim 10 is characterized in that it can be applied to an image forming apparatus such as a printer.

[0019]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing a data flow of a received optical signal in the infrared receiving circuit of the infrared communication apparatus according to the embodiment of the present invention. The infrared receiving circuit according to the embodiment of the present invention includes a photoelectric conversion unit 11, a filter unit 12, and a decoding unit 13. The photoelectric conversion unit 11 has a light receiving unit, and converts the pulse light incident through the light receiving unit into an electric pulse signal according to the pulse width. The filter unit 12 performs filtering on the electric pulse signal converted by the photoelectric conversion unit 11,
Transfer to The decoding unit 13 is an analysis unit of the IrDA signal, and detects the IrDA of the signal transferred from the filter unit 12.
Analyzes the format specified in the standard and recognizes received data.

The operation of each unit will be described. First, light to be received enters a photoelectric conversion unit 11 having a light receiving unit.
The photoelectric conversion unit 11 converts the input pulse light into an electric pulse signal corresponding to the pulse width. The signal converted into the electric pulse signal should have the same pulse width as the optical pulse signal specified in the IrDA standard, but the dynamics of the infrared received light that must be received specified in the standard Because the range is set very large,
Depending on the intensity of the received light, there is a possibility that the pulse signal converted by the photoelectric conversion unit 11 is not always converted into an electric pulse signal conforming to the standard or an electric pulse signal having a pulse width of the received light pulse. For example, FIG.
As shown in FIG. 7, the electric pulse signal may be longer than the received optical pulse width. FIG. 2A shows a waveform of a received optical pulse, and FIG. 2B shows a waveform of an electric pulse after photoelectric conversion.

The electric pulse signal converted as described above is sent to the filter unit 12. In the filter unit 12,
The electric pulse signal converted by the photoelectric conversion unit 11 is filtered and transferred to a decoding unit 13 which is an analysis unit of the IrDA signal. Details of the filtering in the filter unit 12 will be described later. The decoding unit 13 analyzes the format specified in the IrDA standard of the signal sent from the filter unit 12 and performs an operation of recognizing the received data. The data thus received is subjected to various processes according to the purpose.

Next, the operation of the filter unit 12 will be described. The filter unit 12 is added to the infrared communication device in the present invention for the purpose of preventing light that should have been received as a single pulse from being recognized as a double pulse. The optical signal converted into an electric signal in the photoelectric conversion unit 11 may have a longer pulse width due to the sensitivity of the photoelectric conversion or the like. When converting this to a digital signal, if the sampling rate is low,
Depending on the timing of the received signal, a single pulse may be received as a double pulse. If this is analyzed by the decoding unit 13 as it is, it becomes a signal that cannot be originally achieved by IrDA, and a communication error occurs, and there is a danger that communication may not be performed.

FIG. 3 shows this. FIG. 3 (A)
3B, the pulse width is only slightly longer than 125 ns.
When sampling with a sampling clock of MHz,
The signal has a length as shown in FIG. In this case, the pulse width is 187.5 ns, which is a signal that cannot be satisfied by the IrDA standard. This is eventually 8MH
Since it is necessary to sample again at z, FIG.
Whether the signal (C) is recognized as a double pulse or a single pulse is unknown depending on the timing.

However, in IrDA communication, since there is no standard except for a predetermined code, a signal that would have been received as a single pulse can be recognized as a single pulse due to its structure. Performing this operation is the function of the filter unit 12. That is, the filter unit 12
Is added to the infrared communication apparatus for the purpose of preventing light that should have been received as a single pulse from being recognized as a double pulse as described above.

Next, the filtering conditions, that is, the criteria for judging whether the received light is a double pulse or a single pulse will be described below. IrDA 4MHz
In the communication, it is specified that the communication is performed in frame units, and FIG. 8 shows the structure of the frame. Communication is performed using a 4PPM signal in areas other than the preamble, start flag, and stop flag areas. Therefore, a double pulse is generated only in the state of (5) in FIG.

Next, the case of a preamble will be described. 1 when the preamble waveform is receiving light
When no data is received, 0 is represented as one unit for every 125 ns, and a code of "1000, 0000, 1010, 1000" is repeated 16 times. I have. Therefore,
There are no double pulses in the preamble. Also, normal 4PP “0000” and “1010”
In some cases, the signal may take a form that cannot be achieved with the M signal.

Next, the start flag is represented in the same manner as "0000, 1100, 0000, 110".
0, 0110, 0000, 0110, 0000 ". In this case, "0000", "1"
100 "and" 0110 ". Regarding the stop flag, “0000, 1100, 00
00, 1100, 0000, 0110, 0000, 01
10 "is specified. In this case, "00
00 "," 1100 ", and" 0110 ".

When these are combined, the received signal becomes 1
When viewed as 25 ns x 4 bits, "000
In the case of "1", the next signal is "1000", in the case of "0000", the next signal is "1100" or "0110",
In the case of “1100”, it can be said that there is a possibility that a double pulse has been received only when the next signal is “0110”. Further, since no triple pulse is generated, this can also be converted to a double pulse.

Next, the conditions will be described in detail for each bit. FIG. 9 shows the conditions obtained above for each bit. B1 to B4 are data to be determined, and represent 4 bits in order from the first 1 bit of 125 ns × 4 bits. For C1 to C4, it is assumed that the preceding four bits of data for the determined bits B1 to B4 are represented.

First, in the figure, the portion where "normal" is written indicates conditions under which normal 4PPM communication is performed. In this case, there should be only one of the four locations where data exists. Therefore, no condition exists for B1, no data exists for B2 for B2, no data exists for both B1 and B2 for B3, and no data exists for all of B1 to B3 for B4. The condition is that data exists.

Next, conditions for the preamble will be described. As described above, when all the previous 4-bit data are 0, both the data of B1 and the data of B3 may be 1. Therefore, the state of B3 = 1 may exist only when the previous 4-bit data is all 0 and B1 = 1, and it is necessary to add the condition.

The conditions for the start flag and the stop flag will be described. First, when all the previous 4 bits are 0, B1 = B2 = 1, B3 = B4 = 0, or B1 = B2 = 0.
= B4 = 0 and B2 = B3 = 1. Therefore,
The condition of B2 is added with a condition that if all the previous 4 bits are 0, there is a possibility that 1 exists. As for B3, there is a case where all the previous 4 bits are 0 and 1 is present when B1 = 0. Next, for the case where the previous 4 bits are arranged in a sequence of 1100, B1 = B4 =
0, B2 = B3 = 1. At this time, if the previous 4 bits are 1100 for B3, B3 = 1
There is a possibility that the following case may occur. The above conditions are the case where a double pulse occurs in the received signal, and the case where two bits become 1 in one region.

FIG. 4 is a block diagram showing an outline of the filter section 12 of the infrared communication apparatus according to the embodiment of the present invention. The filter unit 12 includes a sampling unit 40, a data latch unit 41, a filtering logic circuit 42, a data storage unit 43, a data transfer parallel / serial conversion unit 44, and a data control signal generation unit 45. I have. In the figure, a solid arrow indicates a data flow, and a dotted arrow indicates a data control line. The photoelectrically converted data is Data-in, and the filtered data is d.
data-out.

The structure of each of the above-mentioned parts will be described in detail together with the operation.
First, the electrical pulse signal that has been photoelectrically converted is sampled by the sampling unit 40 at a multiple frequency that is at least twice the frequency required for sampling, that is, 8 MHz. For example, 16M
Hz sampling (clock-1).
6M). Here, the signal is already a 16 MHz pulse signal. At this time, the sampled data may be deleted as spike noise when two or more data are not continuously present.

Next, the data control signal generator 45 generates a data shift clock (clock-8M) having a frequency of 8 MHz from the above 16 MHz signal. In response to the clock, the signal sampled by the sampling unit 40 is input to the data latch unit 41 having a shift register configuration. Further, the data control signal generation unit 45 generates a data load signal (load) generated when four 8 MHz signals are output.
The data, which has passed through the filtering logic circuit 42 when 4 bits are accumulated, is latched by the data storage unit 43 and the parallel / serial conversion unit 44 for data transfer.

At this time, in the data latch section 41,
By performing this operation every time the data advances by four, the data can be transferred accurately. Therefore, the data control signal generation unit 45 generates a loading timing and stores the data at that timing. Part 4
3 and the data transfer parallel / serial conversion unit 44 loads the data, and generates a load signal every time 4 bits of data are transmitted. At this time, the filtering logic circuit 42 is a logic circuit that passes a filter that meets the conditions of FIG. 9 described above.

The data generated as described above is simultaneously sent to the data storage unit 43 and the data transfer parallel / serial conversion unit 44 for determining the next 4 bits. In the data transfer parallel / serial converter 44,
Serial conversion is performed for each 8 MHz clock, and IrDA
It is sent to a decoding unit 13 which is a code analysis unit.

By repeating the above processing, IrD
Repeat until the reception of A is completed. The pulse generated as described above has already been converted into a state in which it is highly likely that the signal is a signal in a form that can be used in the IrDA standard. For example, when a signal “0001, 1001, 1000” enters the input, the signal is converted to a signal “000110001000” and sent to the decoding unit 13 in a form that can have a correct IrDA.

A circuit as shown in FIG. 5 is given as an example of such a logic circuit. FIG. 5 shows a data latch unit 41, a filtering logic circuit 42,
4 is a circuit diagram illustrating a configuration example of a data storage unit 43 and a data transfer parallel / serial conversion unit 44. FIG. The data latch section 41 to the data transfer parallel / serial conversion section 44 correspond to those in FIG. In FIG. 5, a data latch unit 41 includes a D-FF (D flip-flop) 41.
a, 41b, 41c, and 41d. The filtering logic circuit 42 includes AND elements 42a and 42a.
b, 42c, 42d, 42e, 42f, 42g, OR elements 42h, 42i, 42j, 42k, and exclusive OR element 42m. Further, the data storage unit 43 stores the D-
FFs 43a, 43b, 43c and 43d are provided.

The signal supply state and connection state of each section will be described. A data shift clock (clock-8M) output from the data control signal generation section 45 will be described.
Are the clock inputs of the D-FFs 41a to 41d, AND
The input is supplied to the input of the element 42e and the input of the parallel / serial conversion unit 44 for data transfer. The data load signal (load) output from the data control signal generation unit 45 is supplied to each clock input of the D-FFs 43a to 43d and an input of the data transfer parallel / serial conversion unit 44.

The Q output of the D-FF 41a is
b, and are supplied to the input of the AND element 42a, respectively.
The Q output of the D-FF 41b is the D input of the D-FF 41c,
The Q output of the D-FF 41c is supplied to the respective inputs of the AND elements 42a, 42b, and 42c.
The input is supplied to each input of AND elements 42a, 42b, 42d, 42e and exclusive OR element 42m, and DF
The Q output of F41d is connected to AND elements 42a, 42b, 42
d, each input of the D-FF 43d, and the input of the parallel / serial conversion unit 44 for data transfer.

The outputs of the AND elements 42b and 42c are
The respective signals are supplied to the respective inputs of the R element 42h, and the AND element 42
Each output of d and 42e is supplied to each input of OR element 42i. The output of the AND element 42a is a D-FF 43
D input of a, parallel / serial converter 4 for data transfer
4 and the output of the OR element 42h is D
The D input of the FF 43b and the input of the parallel / serial conversion unit 44 for data transfer are supplied to the D input of the D-FF 43c and the input of the parallel / serial conversion unit 44 for data transfer, respectively. Is done.

The Q output of the D-FF 43a is connected to the AND element 4
2f, supplied to each input of the OR element 42k,
The Q output of F43b is supplied to an AND element 42f and an OR element 42f.
k is supplied to each input of the D-FF 43c, the Q output of the D-FF 43c is supplied to each input of the AND element 42f and the OR element 42k, and the Q output of the D-FF 43d is supplied to the AND element 42d.
f, and are supplied to respective inputs of the OR element 42k.

The output of the AND element 42f is
j and the output of the OR element 42k is AND
The exclusive OR element 42m is supplied to the input of the element 42g.
Is supplied to the input of an AND element 42g,
Each output of the elements 42f and 42g is supplied to an input of an OR element 42j, and an output of the OR element 42j is supplied to an input of an AND element 42c. In this case, the above D-FF
Captures the state of the D input as the Q output and keeps it constant until the next rising edge of the clock.

That is, according to the configuration shown in FIG. 5, the signal sampled by the sampling section 40 is input to the data latch section 41 by the data shift clock (clock-8M) as described above. The data load signal (load) is a data storage unit 43 and a data transfer parallel / serial conversion unit 4 which store the data that has passed through the filtering logic circuit 42 when 4 bits are accumulated.
Latch at 4. The data is simultaneously sent to a data storage unit 43 for determining the next 4 bits and a parallel / serial conversion unit 44 for data transfer, and is serially converted every 8 MHz clock.

FIG. 6 shows the timing of the signal generated by the data control signal generator 45 described above. Load once every 4 times of clock-8M signal
By outputting the signal, the 4 PPM signal is controlled so that the data transfer parallel / serial conversion unit 44 and the data storage unit 43 can load the signal. The first 4 bits can be correctly recognized as a 4PPM signal by starting to count the number of times based on the first data at the time of the preamble.

As described above, according to the embodiment of the present invention, the infrared receiving circuit of the infrared communication device includes the photoelectric conversion unit 11 for converting the received infrared optical signal into an electric signal.
And a filter unit 12 that converts the electric signal so that the electric signal obtained by the photoelectric conversion by the photoelectric conversion unit 11 does not correspond to the determined pattern so as to have the determined pattern.
A decoding unit 13 for analyzing a format defined in the A standard and recognizing the received data, wherein the filter unit 12 is configured such that the electric signal converted by the photoelectric conversion unit 11 has a pulse width longer than a specified pulse width. In this case, when the electric signal is converted so as to have the pattern, and the electric signal converted by the photoelectric conversion unit 11 is sampled as a digital signal, sampling is performed at a frequency twice or more the transfer rate,
The sampling data is filtered to convert the electric signal into the pattern described above, and the IrDA standard of 4 Mb
When the electric signal converted by the photoelectric conversion unit 11 at the time of reception by the ps communication becomes a signal that cannot be in compliance with the IrDA standard, a signal other than the signal corresponding to the pattern is filtered into a possible signal. The following effects are obtained.

In infrared communication such as IrDA, FIR
When receiving a single data signal, if a single pulse signal is originally recognized as a double pulse, the data is returned to a single pulse by referring to the data before the received data so that a data error does not occur. In doing so, if the sampling frequency is reduced as much as possible, save the previous four data and delete all of the four data except when there is a possibility of a double pulse. Accordingly, it is possible to eliminate errors due to reception and reduce the probability of communication errors.

That is, in infrared communication such as IrDA,
When an optical pulse is converted into an impossible form, such as when it is converted into a long pulse without being converted to a fixed pulse width when photoelectrically converted, it is converted into a possible form signal By doing so, there is an effect that the probability of a communication error can be reduced. In addition, it is possible to filter the signal by sampling the received signal at a multiple frequency of twice or more, and to perform filtering on the received signal without using a fast clock for sampling the received signal. Therefore, there is an effect that cost reduction and the like can be achieved. Furthermore, the present invention is not limited to the IrDA standard communication, and has an effect that it can be used when data signals are unstable when performing PPM communication.

The present invention may be applied to a system composed of a plurality of devices or an apparatus composed of one device. Further, the present invention can be applied to an image forming apparatus such as a printer. That is, when performing infrared communication in an image forming apparatus such as a printer to which the infrared receiving apparatus of the present invention is applied, similarly to the above, the probability of a communication error can be reduced, cost can be reduced, and the like. The effect can be achieved.

[0052]

As described above, according to the first aspect of the present invention, there is provided an infrared receiving apparatus for receiving infrared light in a light pattern of a predetermined standard, wherein the received infrared light signal is converted into an electric signal. And a filter for converting an electric signal so that the electric signal becomes the pattern when the electric signal converted by the photoelectric conversion means does not correspond to the pattern. That is, for example, in infrared communication such as IrDA, when an optical signal does not correspond to the pattern when the optical pulse is photoelectrically converted as described above (a long pulse is generated without being converted to a predetermined pulse width). If the electrical signal is in an impossible form due to
Furthermore, there is an effect that the probability of a communication error can be reduced by converting an electric signal (converting into a signal of a possible form) so as to form the pattern. Also, I
The present invention is not limited to the communication of the rDA standard, and has an effect that it can be used when data signals are unstable when performing PPM communication.

According to the second aspect of the present invention, the filter unit of the infrared receiving apparatus is configured to form the pattern when the electric signal converted by the photoelectric conversion unit has a pulse width longer than a specified pulse width. Convert electrical signals. That is, for example, in infrared communication such as IrDA, as described above, when a light pulse is photoelectrically converted and becomes a long pulse without being converted to a determined pulse width,
By converting the electric signal (converting the signal into a possible signal) so as to have the pattern, there is an effect that the probability of a communication error can be reduced.

According to the third aspect of the present invention, when the filter means of the infrared receiving apparatus samples the electric signal converted by the photoelectric conversion means as a digital signal,
Sampling is performed at a frequency twice or more as high as the transfer rate, and the sampling data is filtered to convert an electric signal into the pattern. That is, as described above, it is possible to filter a signal by sampling a received signal at a multiple frequency that is twice or more, without using a fast clock for sampling a received signal. In addition, it is possible to perform filtering on the received signal, and to reduce the cost.

According to the fourth aspect of the present invention, the filter means of the infrared receiver has a signal in a form in which the electric signal converted by the photoelectric conversion means at the time of reception by IrDA-compliant 4 Mbps communication is impossible with the IrDA standard. In this case, a signal other than the signal corresponding to the pattern is filtered to obtain a possible electric signal. That is, in the infrared communication of the IrDA standard, as described above, when an optical pulse is converted into an impossible form of an electric signal when photoelectrically converted, as described above, a communication error of the form is possible by converting the signal into a possible form of signal. The effect is that the probability can be reduced.

According to the invention of claim 5, the infrared receiving apparatus is applicable to an image forming apparatus such as a printer. Therefore, when performing infrared communication in an image forming apparatus such as a printer to which the infrared receiving apparatus of the present invention is applied, similarly to the above, the probability of communication errors can be reduced, cost can be reduced, and the like. effective.

According to a sixth aspect of the present invention, there is provided a signal processing method in an infrared receiving apparatus for receiving infrared light in a light pattern of a predetermined standard, comprising: a photoelectric conversion step of converting a received infrared light signal into an electric signal; And a filter step of converting the electric signal so that the electric signal converted in the photoelectric conversion step does not correspond to the pattern so that the electric signal becomes the pattern. That is, for example, in infrared communication such as IrDA, when an optical signal does not correspond to the pattern when the optical pulse is photoelectrically converted as described above (a long pulse is generated without being converted to a predetermined pulse width). (E.g., when the electrical signal is in an improbable form, for example), the probability of a communication error is reduced by converting the electric signal so as to have the pattern (converting to a possible form signal). There is an effect that can be. Further, the present invention is not limited to the IrDA standard communication, and has an effect that it can be used when data signals are unstable when performing PPM communication.

According to the seventh aspect of the present invention, in the filtering step of the signal processing method in the infrared receiving apparatus, when the electric signal converted in the photoelectric conversion step has a pulse width longer than a specified pulse width, The electric signal is converted so that That is, for example, in the infrared communication such as IrDA, when the optical pulse is photoelectrically converted, as described above, when the pulse is not converted into a predetermined pulse width and becomes a long pulse, the pattern becomes the above-described pattern. Convert electrical signals (convert to possible signal)
This has the effect of reducing the probability of a communication error.

According to the eighth aspect of the present invention, in the filtering step of the signal processing method in the infrared receiving apparatus, when the electric signal converted in the photoelectric conversion step is sampled as a digital signal, the transfer rate is 2
Sampling is performed at twice or more the frequency, and the sampling data is filtered to convert the electric signal into the pattern. That is, as described above, it is possible to filter the signal by sampling the received signal at a multiple frequency of twice or more,
There is an effect that the received signal can be filtered without using a fast clock for sampling the received signal, and the cost can be reduced.

According to the ninth aspect of the present invention, in the above-mentioned filtering step of the signal processing method in the infrared receiving apparatus,
When the electric signal converted in the photoelectric conversion step becomes a signal that cannot be in compliance with the IrDA standard at the time of reception by the rDA standard 4 Mbps communication, signals other than those corresponding to the pattern are filtered to be possible signals. That is, in the infrared communication of the IrDA standard, as described above, when an optical pulse is converted into an impossible form of an electric signal when photoelectrically converted, as described above, a communication error of the form is possible by converting the signal into a possible form of signal. The effect is that the probability can be reduced.

According to the tenth aspect, the signal processing method in the infrared receiving device is applicable to an image forming apparatus such as a printer. Therefore, when performing infrared communication in an image forming apparatus such as a printer to which the signal processing method in the infrared receiving apparatus of the present invention is applied, the probability of a communication error can be reduced and cost reduction can be achieved as in the above. There are effects such as being able to.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a data flow of a received optical signal in an infrared receiving circuit of an infrared communication device according to an embodiment of the present invention.

FIG. 2 is a time chart showing an example of a received signal;
(A) is a time chart showing the received light pulse,
(B) is a time chart showing electric pulses after photoelectric conversion.

3A and 3B are time charts showing an example of sampling of a received signal, wherein FIG. 3A is an explanatory diagram showing a pulse signal, FIG. 3B is a time chart showing a sampling clock, and FIG. 3C is a time chart showing a signal after sampling; It is.

FIG. 4 is a block diagram illustrating an outline of a filter unit of the infrared communication device according to the embodiment of the present invention.

FIG. 5 is a circuit diagram illustrating a configuration example of a data latch unit, a filtering logic circuit, a data storage unit, and a data transfer parallel / serial conversion unit that constitute a filter unit of the infrared communication device according to the embodiment of the present invention. .

FIG. 6 is a time chart showing an example of a data control signal according to the embodiment of the present invention.

FIG. 7 is a time chart showing a correlation between a data pulse and data according to the IrDA standard.

FIG. 8 is an explanatory diagram showing a structure of a frame of the IrDA standard.

FIG. 9 is an explanatory diagram showing a condition according to the embodiment of the present invention for each bit.

[Explanation of symbols]

 Reference Signs List 11 photoelectric conversion unit 12 filter unit 13 decoding unit 40 sampling unit 41 data latch unit 42 filtering logic circuit 43 data storage unit 44 data transfer parallel / serial conversion unit 45 data control signal generation unit

Claims (10)

[Claims] 1. An infrared receiver for receiving infrared light in a light pattern of a predetermined standard, comprising: a photoelectric conversion means for converting a received infrared light signal into an electric signal; and an electric signal converted by the photoelectric conversion means. And a filter means for converting an electric signal so that the pattern becomes the pattern when the pattern does not correspond to the pattern. 2. The apparatus according to claim 1, wherein the filter unit converts the electric signal so as to have the pattern when the electric signal converted by the photoelectric conversion unit has a pulse width longer than a specified pulse width. Item 7. The infrared receiver according to Item 1. 3. When sampling the electric signal converted by the photoelectric conversion unit as a digital signal, the filter unit performs sampling at a frequency twice or more as high as a transfer rate, and filters the sampled data. 2. The infrared receiving apparatus according to claim 1, wherein the electric signal is converted into a pattern. 4. The filter means includes an IrDA (Infrare
d Data Association) When the electric signal converted by the photoelectric conversion means becomes a signal that cannot be in the IrDA standard at the time of reception by the 4 Mbps communication of the standard, an electric signal in a form that can be filtered and possible other than the signal corresponding to the pattern. The infrared receiving apparatus according to claim 1, wherein: 5. The infrared receiving apparatus according to claim 1, wherein the infrared receiving apparatus is applicable to an image forming apparatus such as a printer. 6. A signal processing method in an infrared receiving apparatus for receiving infrared light with a light pattern of a predetermined standard, comprising: a photoelectric conversion step of converting a received infrared light signal into an electric signal; A filter step of converting the electric signal so that the converted electric signal does not correspond to the pattern so that the electric signal becomes the pattern. 7. The method according to claim 1, wherein in the filtering step, when the electric signal converted in the photoelectric conversion step has a pulse width longer than a specified pulse width, the electric signal is converted so as to have the pattern. Item 7. A signal processing method in the infrared receiver according to Item 6. 8. In the filtering step, when sampling the electric signal converted in the photoelectric conversion step as a digital signal, the sampling is performed at a frequency twice or more as high as a transfer rate, and the sampling data is filtered to perform the sampling. 7. The method according to claim 6, wherein the electric signal is converted into a pattern. 9. In the filtering step, when the electric signal converted in the photoelectric conversion step becomes a signal that cannot be compliant with the IrDA standard at the time of reception by IrDA standard 4 Mbps communication, filtering is performed on signals other than the signal corresponding to the pattern. 7. The signal processing method in the infrared receiving apparatus according to claim 6, wherein the electric signal is a possible electric signal. 10. The signal processing method in an infrared receiving apparatus according to claim 6, wherein the signal processing method is applicable to an image forming apparatus such as a printer.