JPH11145912A - Optical reception method and optical receiver - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method capable of coping with the one of a transmission band width larger than before by receiving optical signals, detecting edge information from the received optical signals and generating quantized signals based on the detected edge information. SOLUTION: The output of an optical reception amplifier 104 is edge-detected in an edge detection circuit 105 and an edge detection circuit output waveform is obtained. In the stage, for the response speed limit of a light emitting diode and a photodiode 103, the generated fluctuation of an average voltage is removed and further, the edge information for relatively hardly receiving degradation due to response speed is extracted from a degraded waveform. Then, the waveform is quantized in a quantization circuit 106. In the quantization circuit 106, a rise edge and a fall edge are separately detected and synthesized and a transmission waveform is reproduced. The edge detection circuit output waveform and the reference voltage 109 of a reference voltage level are compared and a rise pulse is obtained in comparator output.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical receiving method and an optical receiving device.

[0002]

2. Description of the Related Art In recent years, devices have become wireless, and among them, optical transmission apparatuses using light as a data transmission medium are increasing.

FIG. 17 shows a circuit configuration of a conventional optical transmission device.
701 is a modulation circuit, 1702 is an LED driver, 170
3 is a light emitting diode, 1704 is a photodiode, 1
705 is a light receiving amplifier, 1706 is a comparator reference voltage, 1707 is a comparator, and 1708 is a demodulation circuit. FIG. 18 shows a signal waveform of each part of the conventional optical transmission device.
1 is a transmission waveform, 1802 is a comparator input waveform, 18
03 is a comparator reference voltage, and 1804 is a comparator output waveform.

[0004] Data to be transmitted is modulated by a 1701 modulation circuit to become a modulated wave like a 1801 transmission waveform. The modulated wave is amplified by a 1702 LED driver and applied to a 1703 light emitting diode. Light emitted from the 1703 light emitting diode is transmitted through space or an optical fiber, received by the 1704 photodiode, and amplified by the 1705 light receiving amplifier. Mainly 1
The waveform deteriorates like the input waveform of the 1802 comparator due to the response speed limitation of the 703 light emitting diode and the 1704 photodiode. However, 17
06 is compared with the reference voltage and quantized to 18
04 It becomes like the comparator output waveform. The output waveform of the 1804 comparator is demodulated by a 1708 demodulation circuit to obtain demodulated data.

In the above example, the data to be transmitted is an NRZ signal. If the data is converted into an RZ signal by a 1701 modulation circuit, the maximum frequency of the modulated wave is twice the data transmission rate. CMI signals and DMIs conventionally used in optical transmission
The maximum frequency also doubles for signals and Manchester codes. Therefore, when realizing higher-speed data communication, the data transmission speed is limited by the response speed of the light emitting diode or the photodiode.

If the NRZ signal is transmitted as it is, the maximum frequency of the modulated wave is the same as the data transmission rate.
As a result, a transmission rate that is twice that of a signal or the like can be obtained. However, as shown in FIG. 18, when the transmission speed exceeds the response speed of the light emitting diode, waveform distortion occurs as in the 1802 comparator input waveform, and the 1804 comparator output waveform generates a bit error.

[0007]

However, the conventional optical transmission apparatus has a problem that the transmission bandwidth is narrow and high-speed data communication cannot be performed for the above-described reasons.

An object of the present invention is to solve the above-mentioned conventional problems and to provide an optical receiving method and an optical receiving apparatus which can cope with a transmission bandwidth wider than the conventional one. I do.

[0009]

According to the first aspect of the present invention, a transmitted optical signal is received, edge information is detected from the received optical signal, and quantization is performed based on the detected edge information. This is an optical receiving method for generating an obtained signal.

According to a fifth aspect of the present invention, there is provided an optical-electrical converting means for receiving a transmitted optical signal and converting the received optical signal into an electric signal, and converting edge information from the converted electric signal. An optical receiving apparatus comprising: signal edge detection means for detecting; and quantization means for generating a signal quantized based on the detected edge information.

As a result, for example, the influence of signal deterioration caused by the light emitting device and the light receiving device can be reduced, and the transmission bandwidth can be widened.

[0012]

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

FIG. 1 shows an example of a binary image transmission device as an optical transmission device according to a first embodiment of the present invention, and FIG. 2 shows signal waveforms at various parts thereof.

As shown in FIG. 1, 101 is an LED driver, 102 is a light emitting diode as electric-to-light converting means, 103 is a photodiode as light-to-electric converting means, 104 is a light receiving amplifier, and 105 is signal edge detecting means. , An edge detection circuit 106, a quantization circuit 106 as quantization means, 108 a comparator, 109 a reference voltage, 110 a comparator, 111 a reference voltage, 112
Is SR-FF. In FIG. 2, reference numeral 201 denotes a transmission waveform;
Is an LED driver output waveform, 203 is a light receiving amplifier output waveform, 204 is an edge detection circuit output waveform, 205 is a rising edge detection reference voltage, 206 is a falling edge detection reference voltage, 207 is a rising edge pulse, 208
Is a falling edge pulse, and 209 is a reproduced waveform.

A transmission waveform 201 is a serial data string to be transmitted, and is amplified by an LED driver 101.
The 01 LED driver output waveform is applied to 102 LEDs. The 101 LED driver is not needed if the small LED drive power is good. The emission light of 102 LED is 103
The light is received by the photodiode and amplified by the 104 light receiving amplifier, but the waveform deteriorates like the output waveform of the 203 light receiving amplifier mainly due to the response speed limitation of the 102 light emitting diode and the 103 photodiode. Note that the 203 light receiving amplifier is 10
If the output level of the three photodiodes is sufficient, it can be omitted.

Next, the output of the light receiving amplifier 203 is subjected to edge detection by a 105 edge detection circuit, and an output waveform of a 204 edge detection circuit is obtained. In this example, the edge detection is performed by subtracting the original signal and the delayed signal using a delay line and an adder, but a differentiating circuit using a resistor and a capacitor may be used. At this stage, the fluctuation of the average voltage generated due to the limitation of the response speed of the light emitting diode and the 103 photodiode is removed, and the edge information which is relatively less susceptible to deterioration due to the response speed is extracted from the deteriorated waveform. . This waveform is quantized by the 106 quantization circuit. In the 106 quantization circuit, the rising edge and the falling edge are separately detected and then combined to reproduce the transmission waveform.

The detailed operation of the 106 quantization circuit is as follows. By comparing the output waveform of the 204 edge detection circuit with the 109 reference voltage of the 205 reference voltage level, a 207 rising edge pulse is obtained in the output of the 108 comparator. Similarly, by comparing the output waveform of the 204 edge detection circuit with the 111 reference voltage of the 206 reference voltage level, 110
A 208 rising edge pulse is obtained at the comparator output. These are combined by the 112SR-FF, and a 209 reproduced waveform is obtained at the output.

In the conventional method, high-speed data in which a bit error has occurred can be transmitted using an LED or a photodiode having a low response speed. This can exceed the limitations of LEDs and photodiodes, which are the most bottlenecks in high-speed optical transmission, and a higher-speed optical transmission device can be realized.

FIG. 3 shows an example of a digital data transmission device as an optical transmission device according to a second embodiment of the present invention, and FIG. 4 shows signal waveforms at various parts thereof.

As shown in FIG. 3, reference numeral 301 denotes an LED driver, 302 denotes a light emitting diode as electric-to-light converting means, 303 denotes a photodiode as light-to-electric converting means, 304 denotes a light receiving amplifier, and 305 denotes signal edge detecting means. 306 is a quantization circuit as quantization means, 307 is a comparator, 308 is a reference voltage, 309 is a comparator, 310 is a reference voltage, 311
Denotes an SR-FF (flip-flop), 312 denotes a clock recovery circuit as clock recovery means, 313 denotes a synchronization signal detection circuit, 314 denotes a PLL, and 315 denotes a D-FF as resampling means.

As shown in FIG. 4, reference numeral 401 denotes a transmission waveform,
02 is an LED driver output waveform, 403 is a light receiving amplifier output waveform, 404 is an edge detection circuit output waveform, 405 is a rising edge detection reference voltage, 406 is a falling edge detection reference voltage, 407 is a rising edge pulse, and 407 is a rising edge pulse.
08 is a falling edge pulse, 409 is a quantized output waveform, 410 is a resampling clock, and 411 is a reproduced waveform. Here, the sampling means of the present invention uses D-
Corresponds to FF315.

A transmission waveform 401 is a serial data string to be transmitted and is amplified by a 301 LED driver and transmitted by a 301 L driver.
The ED driver output waveform is applied to 302 LED. 3
The 01 LED driver is not needed if the small LED drive power is good. The light emitted from the 302 LED is received by the 303 photodiode and amplified by the 304 light receiving amplifier, but the waveform deteriorates like the output waveform of the 403 light receiving amplifier mainly due to the limitation of the response speed of the 302 light emitting diode and the 303 photodiode. Note that the 303 light receiving amplifier can be omitted when the output level of the 303 photodiode is sufficient.

Next, the output of the light receiving amplifier 303 is subjected to edge detection by a 305 edge detection circuit, and an output waveform of the 404 edge detection circuit is obtained. In this example, the edge detection is performed by subtracting the original signal and the delayed signal using a delay line and an adder, but a differentiating circuit using a resistor and a capacitor may be used. At this stage, the fluctuation of the average voltage generated due to the limitation of the response speed of the light emitting diode and the photodiode 303 is removed, and the edge information which is less susceptible to deterioration due to the response speed is extracted from the deteriorated waveform. You. This waveform is quantized by the 306 quantization circuit. The 306 quantization circuit detects the rising edge and the falling edge separately and then combines them to reproduce the transmission waveform.

The detailed operation of the 306 quantization circuit is as follows. By comparing the output waveform of the 404 edge detection circuit with the 308 reference voltage of the 405 reference voltage level, a 407 rising edge pulse is obtained in the output of the 307 comparator. Similarly, 309 is obtained by comparing the output waveform of the 404 edge detection circuit with the 310 reference voltage of the 406 reference voltage level.
A 408 falling edge pulse is obtained at the comparator output. These are combined by the 311SR-FF to obtain a 409 quantized output waveform at the output. The 410 resampling clock having the same frequency as the data transmission rate detects the synchronization signal embedded in the transmission data string by the 313 synchronization signal detection circuit and generates the same by the 314 PLL circuit. The sync signal uses a bit pattern that never appears in normal data to distinguish it from normal data. Note that a method of reproducing a clock from the data string itself without a special synchronization signal may be used. 315D with 410 resampling clocks
A 411 reproduced waveform is obtained by sampling using -FF. Since the sampled data is obtained, digital signal processing can be easily performed. It is to be noted that it is advantageous in terms of hardware that the digital signal processing is performed in synchronization with a clock, and that data sampled with a clock can be obtained by providing the clock reproducing means 312.

In the conventional method, high-speed data in which a bit error has occurred can be transmitted using an LED or a photodiode having a low response speed. This can exceed the limitations of LEDs and photodiodes, which are the most bottlenecks in high-speed optical transmission, and a higher-speed optical transmission device can be realized.

FIG. 5 shows an example of a binary image transmission device as an optical transmission device according to a third embodiment of the present invention, and FIG. 6 shows signal waveforms at various parts thereof.

As shown in FIG. 5, reference numeral 501 denotes an LED driver; 502, a light emitting diode as an electric-to-light converting means; 503, a photodiode as a light-to-electric converting means; , 505 is an edge detection circuit as signal edge detection means, 506 is a quantization circuit as quantization means, 507 is a comparator, 508 is a reference voltage, 509 is a comparator, 510 is a reference voltage, 511 is SR-FF, and 512 is SR-FF. This is a peak detection circuit as signal level detection means.

As shown in FIG. 6, reference numeral 601 denotes a transmission waveform;
02 is an LED driver output waveform, 603 is a variable gain amplifier output waveform, 604 is an edge detection circuit output waveform, 60
5 is a rising edge detection reference voltage, 606 is a falling edge detection reference voltage, 607 is a rising edge pulse, 608 is a falling edge pulse, and 609 is a quantized output waveform.

A transmission waveform 601 is a serial data stream to be transmitted, and is amplified by a 501 LED driver and transmitted.
The 01 LED driver output waveform is applied to 502 LEDs. The 501 LED driver is not needed if the small LED drive power is good. The emission light of 502 LED is 503
The light is received by the photodiode and amplified by the 504 light receiving amplifier, but the waveform deteriorates like the output waveform of the 603 light receiving amplifier mainly due to the limitation of the response speed of the 502 light emitting diode and the 503 photodiode.

Next, the output of the 504 variable gain amplifier is 5
The edge detection is performed by the 05 edge detection circuit, and the output waveform of the 604 edge detection circuit is obtained. The 512 peak detection circuit detects the peak value of the output waveform of the 604 edge detection circuit, and controls the gain of the 504 variable gain amplifier based on the detected peak value.
The amplitude of the output waveform of the 04 edge detection circuit is kept constant. This is due to a change in the transmission distance or deviation of the optical axis.
3 The light receiving state of the photodiode changes, and the change in the amplitude of the output waveform of the 604 edge detection circuit is 507 comparator, 50
9 prevents edge information pulsing of the comparator from failing. The same effect can be obtained by using the RMS value instead of the peak value. In this embodiment, the edge detection is performed by using the delay line and the adder to subtract the original signal and the delayed signal. However, a differentiating circuit using a resistor and a capacitor may be used. At this stage, the fluctuation of the average voltage generated due to the limitation of the response speed of the light emitting diode and the 503 photodiode is removed, and edge information which is relatively less susceptible to deterioration due to the response speed is extracted from the deteriorated waveform. . This waveform is quantized by a 506 quantization circuit. In the 506 quantization circuit, the rising edge and the falling edge are separately detected and then synthesized to reproduce the transmission waveform.

The detailed operation of the 506 quantization circuit is as follows. By comparing the output waveform of the 604 edge detection circuit and the 508 reference voltage of the 605 reference voltage level, a 607 rising edge pulse is obtained in the 507 comparator output. Similarly, by comparing the output waveform of the 604 edge detection circuit with the 510 reference voltage of the 606 reference voltage level, 509 is obtained.
A 608 falling edge pulse is obtained in the comparator output. These are combined by the 511SR-FF, and a 609 reproduced waveform is obtained at the output.

In the conventional method, high-speed data in which a bit error has occurred can be transmitted using an LED or a photodiode having a low response speed. This can exceed the limitations of LEDs and photodiodes, which are the most bottlenecks in high-speed optical transmission, and a higher-speed optical transmission device can be realized.

FIG. 7 shows an example of a digital data transmission device as an optical transmission device according to a fourth embodiment of the present invention, and FIG. 8 shows signal waveforms at various parts thereof.

As shown in FIG. 7, reference numeral 701 denotes an LED driver; 702, a light emitting diode as an electric-to-optical converter; 703, a photodiode as an optical-to-electrical converter; 704, a variable gain amplifier as an amplification factor variable unit. , 705 an edge detection circuit as signal edge detection means, 706 a quantization circuit as quantization means, 707 a comparator, 708 a reference voltage, 709 a comparator, 710 a reference voltage, 711 an SR-FF, and 712 Reference numeral 713 denotes a synchronization signal detection circuit, 714 denotes a PLL, 715 denotes a D-FF as resampling means, and 716 denotes a peak detection circuit as peak detection means.

As shown in FIG. 8, reference numeral 801 denotes a transmission waveform;
02 is an LED driver output waveform, 803 is a variable gain amplifier output waveform, 804 is an edge detection circuit output waveform,
5 is a rising edge detection reference voltage, 806 is a falling edge detection reference voltage, 807 is a rising edge pulse, 608 is a falling edge pulse, 609 is a quantized output waveform, 810 is a resampling clock, and 811 is a reproduction waveform.

The 801 transmission waveform is a serial data string to be transmitted, and is amplified by the 701 LED driver.
The 01 LED driver output waveform is applied to 702 LEDs. The 701 LED driver is not needed if the small LED drive power is good. The emission light of 702 LED is 703
The light is received by the photodiode and amplified by the 704 light receiving amplifier, but the waveform deteriorates like the output waveform of the 803 light receiving amplifier mainly due to the limitation of the response speed of the 702 light emitting diode and the 703 photodiode.

Next, the output of the 703 variable gain amplifier is 7
The edge detection is performed by the 05 edge detection circuit, and the output waveform of the 804 edge detection circuit is obtained. The 712 peak detection circuit detects the peak value of the output waveform of the 804 edge detection circuit, and controls the gain of the 703 variable gain amplifier with the output to detect the peak value.
The amplitude of the output waveform of the 04 edge detection circuit is kept constant. This is due to a change in the transmission distance or deviation of the optical axis.
3 The light receiving state of the photodiode changes, and the change in the amplitude of the output waveform of the 804 edge detection circuit
9 prevents edge information pulsing of the comparator from failing. The same effect can be obtained by using the RMS value instead of the peak value. In this embodiment, the edge detection is performed by using the delay line and the adder to subtract the original signal and the delayed signal. However, a differentiating circuit using a resistor and a capacitor may be used. At this stage, the fluctuation of the average voltage generated due to the limitation of the response speed of the light emitting diode and the 703 photodiode is removed, and the edge information which is relatively less susceptible to deterioration due to the response speed is extracted from the deteriorated waveform. . This waveform is quantized by a 706 quantization circuit. The 706 quantization circuit detects the rising edge and the falling edge separately and then combines them to reproduce the transmission waveform.

The detailed operation of the 706 quantization circuit is as follows. By comparing the output waveform of the 804 edge detection circuit with the 708 reference voltage of the 805 reference voltage level, an 807 rising edge pulse is obtained in the output of the 707 comparator. Similarly, by comparing the output waveform of the 804 edge detection circuit with the 710 reference voltage of the 806 reference voltage level, 709 is obtained.
An 808 falling edge pulse is obtained at the comparator output. These are combined by the 711SR-FF to obtain a 709 quantized output waveform at the output. The 810 resampling clock having the same frequency as the data transmission rate detects the synchronization signal embedded in the transmission data string by the 713 synchronization signal detection circuit and generates the same by the 714 PLL circuit. The sync signal uses a bit pattern that never appears in normal data to distinguish it from normal data. Note that a method of reproducing a clock from the data string itself without a special synchronization signal may be used. 715D with 810 resampling clock
By sampling using -FF, an 811 reproduced waveform is obtained. Since the sampled data is obtained, digital signal processing can be easily performed.

In the conventional method, high-speed data in which a bit error has occurred can be transmitted using an LED or a photodiode having a low response speed. This can exceed the limitations of LEDs and photodiodes, which are the most bottlenecks in high-speed optical transmission, and a higher-speed optical transmission device can be realized.

FIG. 9 shows an example of a digital data transmission device as an optical transmission device according to a fifth embodiment of the present invention, and FIG. 10 shows signal waveforms at various parts thereof.

As shown in FIG. 9, reference numeral 901 denotes an LED driver; 902, a light-emitting diode as electric-to-light conversion means; 903, a photodiode as light-to-electricity conversion means; 904, a light-receiving amplifier; 906 is an edge detection circuit as signal edge detection means, 907 is a quantization circuit as quantization means, 908 is a sign decision unit, and 909 is an SR-FF.

As shown in FIG. 10, 1001 is a transmission waveform, 1002 is an LED driver output waveform, 1003 is a light receiving amplifier output waveform, 1004 is a sampling clock,
1114 denotes output data of the edge detection circuit, 1005 denotes a rising edge pulse, 1006 denotes a falling edge pulse, and 1007 denotes a reproduced waveform.

A transmission waveform 1001 is a serial data stream to be transmitted and is amplified by a 901 LED driver.
An LED driver output waveform is applied to the 902 LED.
The 901 LED driver is not needed if the small LED drive power is good. The light emitted from the 902 LED is received by the 903 photodiode and amplified by the 904 light receiving amplifier, but the waveform deteriorates like the output waveform of the 1003 light receiving amplifier mainly due to the limitation of the response speed of the 902 light emitting diode and the 903 photodiode. 904 light receiving amplifier is 903
This can be omitted if the output level of the photodiode is sufficient.

Next, the output of the 904 light receiving amplifier is 905 A
It is converted to a digital signal by a D converter. At this time, the frequency of the 1004 sampling clock is 100
It must be higher than the data rate of one transmission waveform.
The A / D-converted digital data is subjected to edge detection by a 906 edge detection circuit, and positive 1114 rising edge and negative 1114 falling edge edge detection circuit output data are obtained. At this stage, the fluctuation of the average voltage generated due to the limitation of the response speed of the 902 light emitting diode and the 903 photodiode is removed, and the edge information which is relatively less susceptible to deterioration due to the response speed is extracted from the deteriorated waveform. You. The AD converted digital data is 90
7 is quantized by a quantization circuit. The 906 quantization circuit detects the rising edge and the falling edge separately and then combines them to reproduce the transmission waveform.

The detailed operation of the 907 quantization circuit is as follows. The output data of the 1114 edge detection circuit is judged to be positive or negative by the 908 polarity judgment circuit, and a 1005 rising edge pulse and a 1006 falling edge pulse are detected.
The 9SR-FF synthesizes and 1007 reproduced waveform is obtained at the output. If the 908 polarity determination circuit is provided with a determination threshold value for the rising edge and the falling edge separately instead of the positive / negative determination, the noise resistance performance is improved.

The present invention, in which all signal processing is performed digitally, does not require clock recovery using a PLL or the like, and can employ complicated signal processing in the edge detection circuit and quantization circuit, and is highly reliable against noise and waveform distortion. It can be a circuit. In general, a reduction in size and cost can be expected, but a high-speed device must be used because a sampling clock requires a frequency higher than the data transfer rate.

In the conventional method, high-speed data in which a bit error has occurred can be transmitted using an LED or a photodiode having a low response speed. This can exceed the limitations of LEDs and photodiodes, which are the most bottlenecks in high-speed optical transmission, and a higher-speed optical transmission device can be realized.

FIG. 11 shows an example of a digital data transmission device as an optical transmission device according to a sixth embodiment of the present invention, and FIG. 12 shows signal waveforms at various parts thereof.

As shown in FIG. 11, 1101 is an LED driver, 1102 is a light emitting diode as an electric-to-light converting means, 1103 is a photodiode as a light-to-electric converting means, 1104 is an AGC amplifier as an automatic constant amplitude means, Reference numeral 1105 denotes an AD converter as analog-digital conversion means, 1106 denotes an edge detection circuit as signal edge detection means, 1107 denotes a quantization circuit as quantization means, 1108 denotes a sign decision unit, and 1109 denotes SR-F
F.

As shown in FIG. 12, 1201 is a transmission waveform, 1202 is an LED driver output waveform, and 1203 is A
Reference numeral 1204 denotes a sampling clock, reference numeral 1214 denotes output data of an edge detection circuit, reference numeral 1205 denotes a rising edge pulse, reference numeral 1206 denotes a falling edge pulse, and reference numeral 1207 denotes a reproduction waveform. Here, the signal level compensating means of the present invention uses an AGC as an automatic constant amplitude means.
This corresponds to the amplifier 1104.

The transmission waveform 1201 is a serial data string to be transmitted, and is amplified by the 1101 LED driver, and the output waveform of the 1101 LED driver is applied to the 1102 LED. The 1101 LED driver is not needed if small LED drive power is good. The emitted light of the 1102 LED is received by the 1103 photodiode and amplified by the 1104 light receiving amplifier, but the waveform deteriorates like the output waveform of the 1203 AGC amplifier mainly due to the limitation of the response speed of the 1102 light emitting diode and 1103 photodiode.
The 1203 AGC amplifier secures a signal level in an input voltage range that is optimal for the 1105 AD converter even if the light receiving state of the 1103 photodiode changes due to a change in the transmission distance or a shift in the optical axis.

Next, the output of the 1104 AGC amplifier is 11
It is converted to a digital signal by the 05AD converter. At this time, the frequency of the 1204 sampling clock must be higher than the data rate of the 1201 transmission waveform. The AD converted digital data is subjected to edge detection by a 1106 edge detection circuit, and positive 1204 rising edge and negative 1204 edge detecting circuit output data are obtained. At this stage, the fluctuation of the average voltage generated due to the limitation of the response speed of the 1102 light emitting diode and the 1103 photodiode is removed, and the edge information which is less susceptible to the deterioration due to the response speed is extracted from the deteriorated waveform. Is done. The AD converted digital data is quantized by a 1107 quantization circuit. 110
The 6-quantization circuit detects the rising edge and the falling edge separately and then combines them to reproduce the transmission waveform.

The detailed operation of the 1107 quantization circuit is as follows. The output data of the 1204 edge detection circuit is 110
The polarity determining circuit determines whether the polarity is positive or negative, detects a 1205 rising edge pulse and a 1206 falling edge pulse,
1109 SR-FF synthesizes and 1204 reproduced waveform is obtained in the output. If the 1108 polarity determination circuit is provided with a determination threshold value for the rising edge and the falling edge separately instead of the positive / negative determination, the noise resistance performance is improved.

In the present invention, in which all signal processing is performed digitally, there is no need to reproduce a clock using a PLL or the like, and moreover, complicated signal processing can be adopted for the edge detection circuit and the quantization circuit, and the noise and waveform distortion are highly reliable. It can be a circuit. In general, a reduction in size and cost can be expected, but a high-speed device must be used because a sampling clock requires a frequency higher than the data transfer rate.

In the conventional method, data at a high rate at which a bit error has occurred can be transmitted using an LED or a photodiode having a low response speed. This can exceed the limitations of LEDs and photodiodes, which are the most bottlenecks in high-speed optical transmission, and a higher-speed optical transmission device can be realized.

FIG. 13 shows an example of a digital data transmission device as an optical transmission device according to the seventh embodiment of the present invention, and FIG. 14 shows signal waveforms at various parts thereof.

As shown in FIG. 13, 1301 is an LED driver, 1302 is a light emitting diode as an electric-to-light converting means, 1303 is a photodiode as a light-to-electric converting means, 1304 is a light receiving amplifier, and 1305 is a signal edge detecting means. An edge detection circuit 1306, an AD converter as analog-digital conversion means,
Reference numeral 07 denotes a quantization circuit as quantization means, reference numeral 1308 denotes a sign decision unit, and reference numeral 1309 denotes an SR-FF.

As shown in FIG. 14, reference numeral 1401 denotes a transmission waveform, 1402 denotes an LED driver output waveform, 1403 denotes a light receiving amplifier output waveform, 1404 denotes an edge detection circuit output waveform, 1405 denotes a sampling clock, and 1406 denotes AD.
Converter output data, 1407 is a rising edge pulse, 1408 is a falling edge pulse, and 1409 is a reproduced waveform.

A 1401 transmission waveform is a serial data string to be transmitted, and is amplified by a 1301 LED driver, and a 1402 LED driver output waveform is applied to 1302 LEDs. The 1301 LED driver is not needed if small LED drive power is good. The emitted light of the 1302 LED is received by the 1303 photodiode and amplified by the 1304 light receiving amplifier. However, the waveform deteriorates like the 1403 light receiving amplifier output waveform mainly due to the response speed limitation of the 1302 light emitting diode and the 1303 photodiode. Note that the 1304 light receiving amplifier can be omitted when the output level of the 1303 photodiode is sufficient.

Next, the output of the 1304 light receiving amplifier is 130
Edge detection is performed by a 5-edge detection circuit, and an output waveform of the 1404 edge detection circuit is obtained. In this example, the edge detection is performed by subtracting the original signal and the delayed signal using a delay line and an adder, but a differentiating circuit using a resistor and a capacitor may be used. At this stage 1301
The fluctuation of the average voltage generated due to the limitation of the response speed of the light emitting diode and the 1303 photodiode is removed, and edge information which is relatively less susceptible to deterioration due to the response speed is extracted from the deteriorated waveform. Then 1404
The output waveform of the edge detection circuit is converted into a digital signal by a 1306 AD converter. At this time, the frequency of the 1405 sampling clock must be higher than the data rate of the 1401 transmission waveform. AD converted 1
The output data of the 406 AD converter is quantized by a 1307 quantization circuit. In the 1307 quantization circuit, the rising edge and the falling edge are separately detected and then synthesized,
The transmission waveform is being played.

The detailed operation of the 1307 quantization circuit is as follows. 1406 AD converter output data is 130
An 8 polarity determination circuit determines whether the polarity is positive or negative, and detects a 1407 rising edge pulse and a 1408 falling edge pulse,
The 1409SR-FF synthesizes and a 1409 reproduced waveform is obtained at the output. Note that if the 1408 polarity determination circuit is provided with a determination threshold value for the rising edge and the falling edge separately instead of the positive / negative determination, the noise resistance performance is improved.

According to the present invention, there is no need to reproduce a clock using a PLL or the like, and furthermore, complicated signal processing can be employed in the quantization circuit, and a highly reliable circuit resistant to noise and waveform distortion can be obtained. Further, since the edge detection is performed before the AD conversion, the number of bits of the 1406 AD converter can be reduced and the cost can be reduced. In general, a reduction in size and cost can be expected, but a high-speed device must be used because a sampling clock requires a frequency higher than the data transfer rate.

In the conventional method, high-speed data in which a bit error has occurred can be transmitted using an LED or a photodiode having a low response speed. This can exceed the limitations of LEDs and photodiodes, which are the most bottlenecks in high-speed optical transmission, and a higher-speed optical transmission device can be realized.

FIG. 15 shows an example of a digital data transmission device as an optical transmission device according to the eighth embodiment of the present invention, and FIG. 16 shows signal waveforms at various parts thereof.

In FIG. 15, reference numeral 1501 denotes an LED driver;
02 is a light emitting diode as an electric-optical conversion means, 15
03 is a photodiode as a light-to-electric conversion means, 1
Reference numeral 504 denotes a variable gain amplifier as amplification rate variable means,
505, an edge detection circuit as signal edge detection means;
Reference numeral 1506 denotes an AD as analog-digital conversion means.
Converter, 1507 is a quantization circuit as a quantization means, 1508 is a code determiner, 1509 is an SR-FF, 1
510 is a peak detection circuit as a signal level detection means.

In FIG. 16, reference numeral 1601 denotes a transmission waveform, 1602 denotes an LED driver output waveform, 1603 denotes a variable gain amplifier output waveform, 1604 denotes an edge detection circuit output waveform, 160
5 is a sampling clock, 1606 is AD converter output data, 1607 is a rising edge pulse, 16
08 is a falling edge pulse, and 1609 is a reproduced waveform.

The 1601 transmission waveform is a serial data string to be transmitted, and is amplified by the 1501 LED driver, and the output waveform of the 1602 LED driver is applied to the 1502 LED. The 1501 LED driver is not needed if small LED drive power is good. The light emitted from the 1502 LED is received by the 1503 photodiode and amplified by the 1504 variable gain amplifier. However, the waveform deteriorates like the 1603 variable gain amplifier output waveform mainly due to the response speed limitation of the 1502 light emitting diode and 1503 photodiode. The 1510 peak detection circuit detects the peak value of the output waveform of the 1505 edge detection circuit, and 1505
The amplitude of the output waveform of the 1505 edge detection circuit is kept constant by controlling the gain of the variable gain amplifier. This is because even if the light receiving state of the 1503 photodiode changes due to a change in the transmission distance or a shift in the optical axis, the signal level in the input voltage range optimal for the 1506 AD converter is secured. Next, the output waveform of the 1603 variable gain amplifier is 1505
Edge detection is performed by the edge detection circuit, and an output waveform of the 1604 edge detection circuit is obtained. In this example, the edge detection is performed by subtracting the original signal and the delayed signal using a delay line and an adder, but a differentiating circuit using a resistor and a capacitor may be used. At this stage, the fluctuation of the average voltage generated due to the limitation of the response speed of the 1501 light emitting diode and 1503 photodiode is removed, and the edge information which is relatively less susceptible to deterioration due to the response speed is extracted from the deteriorated waveform. Is done.

Next, the output waveform of the 1604 edge detection circuit is converted into a digital signal by a 1506 AD converter. At this time, the frequency of the 1605 sampling clock must be higher than the data rate of the 1601 transmission waveform. The AD converted 1606 AD converter output data is quantized by a 1507 quantization circuit. 150
The 7 quantization circuit detects the rising edge and the falling edge separately and then combines them to reproduce the transmission waveform.

The detailed operation of the 1507 quantization circuit is as follows. 1606 AD converter output data is 150
An 8 polarity judgment circuit judges positive / negative, detects a 1607 rising edge pulse and a 1608 falling edge pulse,
A 1609SR-FF synthesizes and a 1609 reproduced waveform is obtained at the output. Note that if the 1608 polarity determination circuit is provided with a determination threshold value for the rising edge and the falling edge separately instead of the positive / negative determination, the noise resistance performance is improved.

According to the present invention, there is no need to reproduce a clock using a PLL or the like, and furthermore, a complicated signal processing can be employed in the quantization circuit, and a highly reliable circuit resistant to noise and waveform distortion can be obtained. In general, a reduction in size and cost can be expected, but a high-speed device must be used because a sampling clock requires a frequency higher than the data transfer rate.

In the conventional method, data at a high rate at which a bit error has occurred can be transmitted using an LED or a photodiode having a low response speed. This can exceed the limitations of LEDs and photodiodes, which are the most bottlenecks in high-speed optical transmission, and a higher-speed optical transmission device can be realized.

As described above, the first invention of the present invention is an optical transmission method for transmitting data using the edge of an optical pulse in an optical transmission device, and has an effect that a transmission band can be widened. Having.

According to a second invention, in an optical transmission device,
Comprising an electro-optical converter, an optical-electric converter, a signal edge detector, and a quantizer, wherein an electric signal to be transmitted is converted into light by the electro-optical converter and input to the light-electric converter, An output signal of the optical-to-electrical conversion means is input to the signal edge detection means, and an output signal of the signal edge detection means is input to the quantization means. This has the effect that the band can be widened.

A third aspect of the present invention relates to an optical transmission device,
The electric-to-optical conversion means, the light-to-electricity conversion means, the signal edge detection means, the quantization means, the clock reproduction means, and the resampling means are provided, and the electric signal to be transmitted is converted to light by the electric-to-light conversion means. Input to an optical-electrical conversion means, an output signal of the optical-electrical conversion means is input to the signal edge detection means, an output signal of the signal edge detection means is input to the quantization means, This is an optical transmission device characterized in that an output signal is input to the clock recovery means and the resampling means, and has an effect that a transmission band can be widened. According to a fourth aspect of the present invention, there is provided an optical transmission device, comprising: an electrical-optical converter, an optical-electrical converter, a signal edge detector, a quantizer, a clock reproducer, a resampler, an amplification factor variable unit, and a signal level detector. An electric signal to be transmitted is converted into light by the electric-optical conversion means, input to the optical-electric conversion means, and an output signal of the optical-electric conversion means is input to the amplification rate variable means, An output signal of the amplification rate variable unit is input to the signal edge detection unit, an output signal of the signal edge detection unit is input to the quantization unit and the signal level detection unit, and an output signal of the quantization unit is An optical transmission apparatus characterized in that the signal is input to a clock recovery means and the resampling means, and the output signal of the signal level detection means is input to the amplification rate varying means. It has the effect of being able to localize.

According to a fifth aspect of the present invention, in an optical transmission device,
An electrical-optical converter, an optical-electrical converter, an analog-digital converter, a signal edge detector, and a quantizer, wherein the electrical signal to be transmitted is converted into light by the electrical-optical converter, and The output signal of the optical-electrical conversion means is input to the analog-digital conversion means, the output signal of the analog-digital conversion means is input to the signal edge detection means, and the signal edge detection is performed. This is an optical transmission device characterized in that an output signal of the means is input to the quantization means, and has an effect that a transmission band can be widened.

According to a sixth aspect of the present invention, in an optical transmission device,
An electrical-optical converter, an optical-electrical converter, an analog-digital converter, a signal edge detector, a quantizer, and an automatic constant amplitude unit;
The light is converted into light by light conversion means, input to the light-electric conversion means, an output signal of the light-electric conversion means is input to the automatic constant amplitude means, and an output signal of the automatic constant amplitude means is converted to the analog signal. Input to digital conversion means, the output signal of the analog-digital conversion means is input to the signal edge detection means, the output signal of the signal edge detection means,
This is an optical transmission device characterized in that it is input to the quantization means, and has an effect that a transmission band can be widened.

According to a seventh aspect of the present invention, in an optical transmission device,
An electrical-optical converter, an optical-electrical converter, an analog-digital converter, a signal edge detector, and a quantizer, wherein the electrical signal to be transmitted is converted into light by the electrical-optical converter, and The output signal of the optical-electrical conversion means is input to the analog-digital conversion means, the output signal of the analog-digital conversion means is input to the signal edge detection means, and the signal edge detection is performed. This is an optical transmission device characterized in that an output signal of the means is input to the quantization means, and has an effect that a transmission band can be widened.

According to an eighth invention, in an optical transmission device,
An electrical-optical converter, an optical-electrical converter, a signal edge detector, an analog-digital converter, and a quantizer, wherein an electrical signal to be transmitted is converted into light by the electrical-optical converter, and The output signal of the optical-electrical conversion means is input to the signal edge detection means, the output signal of the signal edge detection means is input to the analog-digital conversion means, and the analog-digital conversion is performed. This is an optical transmission device characterized in that an output signal of the means is input to the quantization means, and has an effect that a transmission band can be widened.

The ninth invention is directed to an optical transmission device,
An electrical-optical converter, an optical-electrical converter, an analog-digital converter, a signal edge detector, a quantizer, a variable amplification factor, and a signal level detector. Means, the signal is input to the light-to-electricity conversion means, the output signal of the light-to-electricity conversion means is input to the gain variable means, and the output signal of the gain variable means is the signal edge detection means. And enter
An output signal of the signal edge detection means is input to the analog-digital conversion means and the signal level detection means,
An output signal of the analog-digital conversion means is input to the quantization means, and an output signal of the signal level detection means is input to the amplification variable means, wherein the optical transmission device, This has the effect that the transmission band can be widened.

As described above, according to the present embodiment, the data transmission band limited by the conventional light emitting device and light receiving device can be exceeded, and an advantageous effect that larger capacity optical transmission can be achieved. can get.

[0081]

As is apparent from the above description, the present invention has an advantage that the transmission bandwidth can be wider than that of the prior art.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an optical transmission device according to a first embodiment of the present invention.

FIG. 2 is a diagram showing signal waveforms of the optical transmission device according to the first embodiment of the present invention.

FIG. 3 is a configuration diagram of an optical transmission device according to a second embodiment of the present invention.

FIG. 4 is a diagram showing signal waveforms of an optical transmission device according to a second embodiment of the present invention.

FIG. 5 is a configuration diagram of an optical transmission device according to a third embodiment of the present invention.

FIG. 6 is a diagram showing signal waveforms of an optical transmission device according to a third embodiment of the present invention.

FIG. 7 is a configuration diagram of an optical transmission device according to a fourth embodiment of the present invention.

FIG. 8 is a diagram showing a signal waveform of an optical transmission device according to a fourth embodiment of the present invention.

FIG. 9 is a configuration diagram of an optical transmission device according to a fifth embodiment of the present invention.

FIG. 10 is a diagram showing signal waveforms of an optical transmission device according to a fifth embodiment of the present invention.

FIG. 11 is a configuration diagram of an optical transmission device according to a sixth embodiment of the present invention.

FIG. 12 is a diagram showing signal waveforms of an optical transmission device according to a sixth embodiment of the present invention.

FIG. 13 is a configuration diagram of an optical transmission device according to a seventh embodiment of the present invention.

FIG. 14 is a diagram showing signal waveforms of an optical transmission device according to a seventh embodiment of the present invention.

FIG. 15 is a configuration diagram of an optical transmission device according to an eighth embodiment of the present invention.

FIG. 16 is a diagram showing signal waveforms of an optical transmission device according to an eighth embodiment of the present invention.

FIG. 17 is a configuration diagram of a conventional optical transmission device.

FIG. 18 is a diagram showing a signal waveform of a conventional optical transmission device.

[Explanation of symbols]

 101 LED Driver 102 Light Emitting Diode 103 Photo Diode 104 Light Receiving Amplifier 105 Edge Detection Circuit 106 Quantization Circuit 107 Comparator 108 Reference Voltage 109 Comparator 110 Reference Voltage 111 SR-FF

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI H04B 10/152 10/142

Claims (15)

[Claims] 1. An optical receiving apparatus comprising: receiving a transmitted optical signal; detecting edge information from the received optical signal; and generating a quantized signal based on the detected edge information. Method. 2. The optical receiving method according to claim 1, wherein the transmitted optical signal is an optical pulse, and the optical pulse is emitted into space. 3. The optical receiving method according to claim 1, wherein the transmitted optical signal is an optical pulse, and the optical pulse is transmitted through an optical fiber. 4. The optical receiving method according to claim 1, wherein said optical signal is an infrared ray. 5. An optical-electrical converting means for receiving a transmitted optical signal and converting the received optical signal into an electric signal; and a signal edge detecting means for detecting edge information from the converted electric signal. An optical receiving apparatus comprising: a quantizing unit configured to generate a signal quantized based on the detected edge information. 6. The apparatus according to claim 5, further comprising sampling means for sampling and outputting an output signal from said quantizing means using the generated clock signal.
The optical receiving device as described in the above. 7. An amplification variable means for amplifying an output signal from the photoelectric conversion means at a predetermined amplification rate, and a signal level of an output signal of the signal edge detection means is detected, and based on the detection result, 7. The optical receiving apparatus according to claim 5, further comprising: a signal level detecting unit that controls the amplification factor, wherein an output signal of the amplification factor varying unit is input to the quantization unit. 8. An analog-to-digital converter for converting an output signal from said photoelectric converter into an analog signal and outputting a result of the conversion to said signal edge detector. Optical receiver. 9. A signal level correction means for receiving an output signal from said photoelectric conversion means as an input, shaping the signal level so as to correct a predetermined level, and outputting to said analog-digital conversion means. The light receiving device according to claim 5, wherein: 10. An optical receiver according to claim 5, further comprising an analog-to-digital converter for AD-converting an output signal from said signal edge detector and outputting the conversion result to said quantizer. apparatus. 11. An amplification rate varying means for amplifying an output signal from said photoelectric conversion means at a predetermined amplification rate, and a signal level of an output signal of said signal edge detection means is detected, and based on the detection result, 11. A signal level detecting means for controlling the amplification factor, wherein an output signal of the amplification factor varying means is inputted to the analog-digital conversion means.
The optical receiving device as described in the above. 12. The optical receiver according to claim 5, wherein the transmitted optical signal is a signal output from a light emitting diode. 13. The optical receiving device according to claim 5, wherein said light-to-electricity conversion means is a photodiode. 14. The optical receiving apparatus according to claim 5, wherein said quantizing means separately detects and combines rising edges and falling edges. 15. The optical receiving apparatus according to claim 7, wherein said signal level detecting means detects a peak value, an RMS value, or an average value.