KR100334773B1 - Apparatus for multi-bit-rate decision in optical transmitting system - Google Patents

Abstract

The present invention relates to an apparatus for determining multiple transmission speeds in an optical transmission system, and the disclosed apparatus is a transmission speed-independent optical reception device, which delays a received transmission signal by a first time and delays the first delayed signal and the reception. A high speed discrimination signal generator for generating exclusive fast summation and low pass filtering to generate a high speed discrimination signal having a level corresponding to a transmission speed of the transmission signal; A low speed discrimination signal having a level corresponding to the transmission speed by delaying the transmission signal by a second time set longer than the first time, exclusively ORing the delayed second delay signal and the received signal, and performing low pass filtering. A low speed discrimination signal generator; And a processor for determining the transmission speed based on the level of the high speed discrimination signal and the level of the low speed discrimination signal.

Description

Multiple transmission rate determination device in optical transmission system {APPARATUS FOR MULTI-BIT-RATE DECISION IN OPTICAL TRANSMITTING SYSTEM}

The present invention relates to an optical receiving apparatus of an optical transmission system, and more particularly, to an apparatus for determining multiple transmission speeds of an optical receiving apparatus.

In general, in the optical transmission system, various protocols and corresponding bit rates may be employed. For example, in the Distributed Data Interface (FDDI), Enterprise System CONnectivity (ESCON), Fiber Channel, Gigabit Ethernet, Asynchronous Transfer Mode (ATM), the transfer rates are 125 Mbps, 155 Mbps, and 200 Mbps, respectively. 622Mbps, 1062Mbps, 1.25Gbps, 2.5Gbps.

As such, one protocol / transmission rate suitable for the optical transmission system is appropriately selected from among various protocols and transmission rates thereof. In the optical transmission system employing such one protocol / transmission rate, the transmission speed of the optical signal is set in advance, so that the optical receiver provided in the repeater or the terminal is designed to operate exclusively to the set protocol and transmission rate.

A wavelength division multiplexing (WDM) system and a long distance optical communication system are composed of a transmitter, a transmission line, an optical amplifier, a node, a receiver, and the like. In the case where the slave transmission data is connected to the optical transmission device, each node is provided with an apparatus for relaying the input data to a wavelength suitable for the optical communication system. Commercially available relays relay data at a fixed rate, but the repeater disclosed in patent application No. 1999-32170 (transmission rate independent photoreceiving method and apparatus) filed by the present applicant has multiple transmission rates. For example, it can relay data of 45Mbps, 125Mbps, 155Mbps, 200Mbps, 622Mbps, 1Gbps, 1.25Gbps, 2.5Gbps. The repeater of Patent Application No. 1999-32170 uses an exclusive OR gate (XOR) and a low pass filter to determine the transmission speed in the processor of the repeater to relay data. Such a relay device is a method of determining a transmission speed by comparing a lookup table stored in a processor of the relay device and an output voltage passing through an exclusive OR gate and a low pass filter in determining a data transmission speed.

However, in some data intervals, an error occurs because the magnitude of the discrimination voltage of the transmission rate is dense and the obscurity of the transmission rate is determined. That is, in the section where the transmission speed is dense (for example, 125Mbps, 155Mbps, 200Mbps), the discrimination range is dense and the discrimination voltage size of the transmission rate is all transmitted due to the performance change of the exclusive OR gate and the low band filter according to the temperature change. Violation of the voltage range of the speed causes a problem that causes an error in the determination of the transmission speed. That is, the performance change of the exclusive ration gate and the low pass filter according to the temperature change with respect to the transmission speed with a small magnitude of the discrimination voltage causes a transmission speed determination error, that is, a link failure.

Accordingly, an object of the present invention is to create a reference table by dividing the exclusive OR gate and the low pass filter output into a dense and a non-dense section of the transmission speed at a transmission speed at which the discrimination voltage is dense. The present invention provides an apparatus for determining multiple transmission speeds of an optical communication system that minimizes discrimination errors caused by changes in performance of exclusive OR gates and low pass filters due to temperature changes in a compact size region.

In order to achieve the above object, the present invention provides a transmission speed independent optical receiving apparatus,

Delay the received transmission signal by a first time, perform an exclusive inverse operation on the delayed first delay signal and the received signal, and perform low pass filtering to generate a high speed discrimination signal having a level corresponding to the transmission speed of the transmission signal; A high speed discrimination signal generator;

A low speed discrimination signal having a level corresponding to the transmission speed by delaying the transmission signal by a second time set longer than the first time, exclusively ORing the delayed second delay signal and the received signal, and performing low pass filtering. A low speed discrimination signal generator; And

And a processor for determining the transmission speed based on the level of the high speed discrimination signal and the level of the low speed discrimination signal.

1 is a block diagram of an optical receiving apparatus including a multiple transmission rate determining apparatus according to an embodiment of the present invention.

2 is a graph showing the relationship between the voltage level of the high speed discrimination signal for multiple transmission rates according to the present invention;

3 is a graph showing the relationship between the voltage level of the low speed determination signal for the multiple transmission rate according to the present invention.

In the optical transmission system, an optical receiver includes a photoelectric conversion unit, an amplifier, a reproduction circuit, a reference clock generator, a determination unit, and an all-optical conversion unit. At this time, the multiple transmission rate determination device in the optical receiver according to the present invention determines the transmission rate by dividing the transmission rate into a dense section and a non-dense section. For example, the optical receiving apparatus according to an embodiment of the present invention includes a high speed discrimination signal generator and a low speed discrimination signal generator, respectively, to determine the transmission speed for monitoring and determining the transmission rate conversion. Hereinafter, with reference to the accompanying drawings will be described a preferred embodiment of the present invention; In describing the present invention, detailed descriptions of related well-known functions or configurations are omitted in order not to obscure the subject matter of the present invention.

1 is a block diagram showing an optical receiver according to the present invention. Referring to FIG. 1, an optical receiver according to the present invention includes a photoelectric conversion unit 101 for converting an input optical signal input at an arbitrary transmission rate into an electrical reception signal, and an electrical reception output from the photoelectric conversion unit 101. An amplifier 102 for amplifying the signal, a transmission rate determination signal generator 130 for receiving a received signal amplified by the amplifier 102 and outputting a signal for recognizing a transmission rate, and the transmission rate determination signal The reference clock generator 103 generating a reference clock according to the transmission rate output from the generator 130 and the received signal output from the amplifier 102 are generated by the reference clock generator 103. Regeneration circuit 104 (CDR: Clock and Data Recovery) for reproducing the clock and data according to the reference clock, and all-optical conversion unit 105 for converting the electrical signal output from the regeneration circuit 104 into an optical signal do. Here, the transmission rate determination signal generator 130 according to the present invention receives the received signal amplified by the amplifier 102 and outputs a signal for determining the high speed transmission rate to determine the high speed transmission signal 106 And a low speed discrimination signal generator 107 which receives a received signal amplified by the amplifier 102 and outputs a signal for determining a low transmission speed.

The high-speed discrimination signal generator 106 delays one signal among signals separated into two identical signals amplified by the amplifier 102 in advance, generates a recognition signal by comparing the original signal with each time zone, and generates the recognition signal. Low pass filtering generates a high speed signal through the output voltage level. In addition, the low speed discrimination signal generator 107 delays another signal in advance to generate a recognition signal by comparing the original signal with each time zone, and generates a low speed signal through a low pass filtering of the recognition signal. Generate. These high speed and low speed signals pass through the processor 108 and are respectively determined. The reference clock generator 103 selectively operates the internal oscillator to generate the same reference clock as the recognized high speed and low speed. The reproducing circuit 104 is a programmable circuit, and not only reshaping and regeneration of a received signal according to the reference clock generated by the reference clock generator 103, but also retiming it. To play.

Specifically, the transmission rate determination signal generator 130 according to an embodiment of the present invention will be described. The high-speed discrimination signal generator 106 according to an embodiment of the present invention is a time delay unit 110 for a high-speed transmission rate of delaying and outputting one signal of a signal divided into two identical signals by a predetermined time ( An exclusive OR gate 111 (XOR: exclusive), which performs an exclusive OR operation on the signal delayed by the high speed delay unit 110 and the original received signal, hereinafter, refers to an exclusive signal. An OR gate, a low pass filter 112 (LPF: Low Pass Filter) for receiving the recognition signal output from the exclusive OR gate 111 and performing low pass filtering and outputting the low pass filter; The analog / digital converter 113 (ADC) converts the analog signal of the output of the signal into a digital signal. The signal output from the analog / digital converter 113 is input to the processor 108 to determine the transmission speed. The determined signal is input to the reference clock generator 103 through the decoder 109.

In addition, the low speed discrimination signal generator 107 is a time delay unit 115 (hereinafter referred to as "low delay") for a low transmission rate for delaying and outputting one signal of a signal separated into two identical signals by a predetermined time. &Quot; ", an exclusive OR gate 116 that performs an exclusive OR operation on the signal delayed by the low speed delay unit 115 and the original received signal to form a transmission signal as a recognition signal, and the exclusive integrating gate 116. The low pass filter 117 receives the recognition signal outputted from the low pass filter and outputs the low pass filter, and the analog / digital converter 118 converts the analog signal of the low pass output into a digital signal. The signal output from the analog / digital converter 118 is input to the processor 108 to determine a low transmission speed.

In this case, in the method of extracting the delay signal of the high speed discrimination signal generator 106, one signal of the output signal of the amplifier 102 is transmitted along the high speed delay unit 110 and the transmission line 110a. Time delay of fast delay 110 relative to 110a is used. For example, a high-speed delay 110 (or delay element, or delay line) is made to be 200ps, which is 1/2 of a 400Gbps non-return zero (NRZ) data one-bit time interval 400ps (picoseconds). Assuming a time delay of 200 ps, the output of the low pass filter 112 of the high speed discrimination signal generator 106 is proportional as shown in FIG.

As shown in FIG. 3, in the delay signal extraction method of the low speed discrimination signal generator 107, another signal of the output signal of the amplifier 102 is transmitted along the low speed delay unit 115 and the transmission line 115a. As such, the time delay of the slow delay 115 relative to the transmission line 115a is used. For example, make a slow delay 115 (or delay element, or delay line) to be less than 200 Mbps one half one bit time interval. Assuming a time delay of 4 ns (nanosecond), the output of the low pass filter 117 of the low speed discrimination signal generator 107 is proportional as shown in FIG.

According to the above configuration, as shown in FIG. 1, after the outputs of the exclusive OR gates 107 and 110 and the low pass filter 108 and 111 are divided into the high speed discrimination signal generator and the low speed discrimination signal generator at multiple transmission rates, the transmission rate is determined. After writing the voltage table in the memory of the processor, the transmission speed of the optical signal inputted to the photoelectric converter 101 reads the outputs of the low pass filters 108 and 111 from the analog / digital converter 112. The processor 113 compares the lookup table with the values in memory. The reference clock frequency is changed by comparing the reference rate table with the magnitude of the transmission rate discrimination voltage, and the same data as the data input to the photoelectric converter 101 is converted and retransmitted by the all-optical converter 105 into an optical signal. Such a method eliminates discrimination errors caused by performance changes of the calculation units 107 and 110 and the low pass filters 108 and 111 that occur in the discrimination interval of the discrimination signal.

(Reference table)

High speed discrimination signal voltage Low speed signal voltage Transmission speed 2.5V 2.5V 2.5 Gbps 1.25 V 2.5V 1.25 Gbps 1.0 V 2.5V 1 Gbps 0.625 V 2.5V 622 Mbps 0.2V 2.0V 200 Mbps 0.12 V 1.55 V 125 Mbps 0.05V 0.45V 45 Mbps

The principle of extraction of the transmission rate and the selection of the reference clock using the reference table is as follows. If the low-pass filter output voltage of the high-speed discrimination signal generator is 2.5V and the output voltage of the low-pass filter of the low-speed discrimination signal generator is 2.5V, the transmission speed is 2.5 Gbps, so that the processor can reproduce the 2.5 Gbps data in the reproduction circuit. A reference clock is selected via 114 (shown in FIG. 1). In the same way, if the low-speed data output of the low-pass filter generation unit is 0.5V and the output voltage of the low-pass filter of the low-speed discrimination signal generator is 1.55V, the transmission speed is 155Mbps. The reference clock is selected via the decoder 114 to reproduce 155 Mbps data in the reproducing circuit.

As a result, when the present invention is adopted in the optical transmission device, the transmission speed discrimination confusion due to the compactness of the discrimination signal is divided into the high speed discrimination signal generator and the low speed discrimination signal generator in the section in which the discrimination voltage of the optical receiver is dense. By eliminating the present invention, it is possible to implement a stable optical transmission optical transmitter and optical receiver in the optical transmission device.

Meanwhile, in the detailed description of the present invention, specific embodiments have been described, but it will be apparent to those skilled in the art that various modifications can be made without departing from the scope of the present invention.

As described above, in the present invention, in determining the transmission speed of a signal transmitted from an optical receiving apparatus, the transmission speed is divided into a high speed discrimination signal generator and a low speed discrimination signal generator by dividing a section having a dense transmission speed into a DC voltage. By discriminating, it is possible to widen the discrimination range to prevent errors in determining the transmission rate and to determine a stable transmission rate.

Claims (3)

In the optical transmission device of the transmission rate independent of, Delay the received transmission signal by a first time, perform an exclusive inverse operation on the delayed first delay signal and the received signal, and perform low pass filtering to generate a high speed determination signal having a level corresponding to the transmission speed of the transmission signal; A high speed discrimination signal generator; A low speed discrimination signal having a level corresponding to the transmission speed by delaying the transmission signal by a second time set longer than the first time, exclusively ORing the delayed second delay signal and the received signal, and performing low pass filtering. A low speed discrimination signal generator; And And a processor for determining the transmission speed based on the level of the high speed discrimination signal and the level of the low speed discrimination signal. The method of claim 1, wherein the high speed discrimination signal generator A time delay unit for a high data rate for delaying the signal by a first time and outputting the first delay signal; An exclusive OR gate for performing an exclusive OR operation on the first delayed signal and the received transmission signal delayed by the time delay unit for the high transmission rate; A low pass filter for low pass filtering the output signal of the exclusive OR gate; And And an analog / digital converter configured to convert the output signal of the low pass filter into a digital signal and output the digital signal as the high speed discrimination signal. The method of claim 1, wherein the low speed determination signal generation unit A time delay unit for a low transmission rate for delaying the signal by a first time and outputting the first delay signal; An exclusive OR gate for performing an exclusive OR operation on the first delayed signal delayed by the time delay unit for the low transmission rate and the received transmission signal; A low pass filter for low pass filtering the output signal of the exclusive OR gate; And And an analog / digital converter configured to convert the output signal of the low pass filter into a digital signal and output the digital signal as the low speed discrimination signal.