KR20220095708A - All Digital Optical Signal Detection Circuit Using a Counter Inside a Clock Data Recovery IC - Google Patents

Abstract

According to one embodiment of the present disclosure, provided is a digital light signal detection circuit. The digital light signal detection circuit may comprise: a first counter that counts the number of 1s from an electrical signal converted in a light element and outputs a high signal when a counted value is greater than 1; a second counter that counts the number of 0s from the electrical signal converted in the light element and outputs the high signal when the counted value is greater than 1; and an AND gate that determines whether a light signal exists based on the output signal from the first counter and the second counter. The first counter and the second counter may be reset every 32 times of the data rate by the reference clock. Therefore, the present invention can be operated more stably.

Description

All Digital Optical Signal Detection Circuit Using a Counter Inside a Clock Data Recovery IC

The present disclosure relates to an optical signal detection circuit, and more particularly, to an all-digital optical signal detection circuit using a counter and reference clock for built-in CDR.

The demand for bandwidth in wired communication is increasing, and thus the use of small optical modules is increasing. Therefore, a low-cost, high-efficiency and stable optical signal sensing technique is required.

The conventional method using a sophisticated comparator or analog filter is an analog method that requires sophisticated circuit design techniques or may be sensitive to process changes or changes in the surrounding environment.

An object of the present disclosure to solve this problem is to provide an all-digital optical signal sensing circuit using a counter for a CDR built-in and a reference clock.

According to an embodiment of the present disclosure, a digital optical signal sensing circuit is provided. The digital optical signal detection circuit may include: a first counter that counts the number of 1's from the electrical signal converted by the optical device and outputs a HIGH signal when the counted value is greater than 1; a second counter for counting the number of zeros from the electrical signal converted by the optical device and outputting a high signal when the counted value is greater than one; and an AND gate that determines whether an optical signal is present based on output signals from the first counter and the second counter. The first counter and the second counter may be reset every 32 times the data rate by a reference clock.

Since all of the optical signal sensing circuits according to the present disclosure are digital circuits, they can be easily synthesized and operated more stably because they are not sensitive to the process or environment compared to the analog circuit method.

In addition, the optical signal sensing circuit according to the present disclosure is a digital circuit and occupies less space because the number of gates is small and thus the cost is low, the detection accuracy is high because an accurate reference clock is used, and the sensing function is a digital circuit Post-processing such as filtering is easy.

1 is a schematic diagram illustrating a digital optical signal sensing circuit according to an embodiment of the present disclosure;

Various aspects of the present disclosure are described below. It is to be understood that the inventions presented herein may be embodied in a wide variety of forms and that any specific structure, function, or both, presented herein is exemplary only. Based on the inventions presented herein, those of ordinary skill in the art will recognize that one aspect presented herein may be implemented independently of any other aspects, and that two or more of these aspects may vary in various ways. It will be understood that they can be combined with For example, an apparatus may be implemented or a method may be practiced using any number of the aspects set forth herein. Moreover, such an apparatus may be implemented or such a method may be practiced using other structure, function, or structure and functionality in addition to or other than one or more aspects described herein.

According to the present disclosure, a small optical module receives an optical signal and converts an optical signal into an electrical signal (receiving end is ROSA, transmitting end is TOSA) and CDR IC (Clock) that receives the electrical signal converted from the optical device and restores the signal and clock data recovery IC). In addition, a reference clock using a crystal may exist in the optical module.

The signal pattern of the wired communication network always has that of a PRBS signal, and the pattern that most differs from the average frequency of the signal is PRBS-31. That is, the worst case in terms of frequency may be a case in which 31 signals are consecutive, for example, a case in which a signal of 0 is consecutive 31 times after a 1 is generated.

Accordingly, the optical signal detection circuit of the present disclosure may be configured to detect the presence of an optical signal when an electrical signal converted in an optical device is input to a CDR and 1 or 0 occurs even once within a section for 32 data lengths.

1 is a schematic diagram illustrating a digital optical signal sensing circuit according to an embodiment of the present disclosure;

1 , the optical signal sensing circuit may include two counters and an AND gate. The two counters can count the number of 0's and 1's, respectively, from the point in time when the reset occurs (where the reset may correspond to 32 times the data rate using the reference clock). Each of the two counters may generate a HIGH signal as an output signal when the counted value is greater than 1, and the output signal of each of the two counters may be input to an AND gate.

The output of the AND gate may be a result of finally detecting whether an optical signal is present. For example, when signals from counters input to the AND gate are all HIGH signals, the AND gate may output a HIGH signal, and the optical signal detection circuit determines that an optical signal exists by outputting the HIGH signal of the AND gate. can

The description of the presented embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the scope of the invention. Thus, the present invention is not to be limited to the embodiments presented herein, but is to be construed in the widest scope consistent with the principles and novel features presented herein.

Claims (1)

A digital optical signal sensing circuit comprising:
a first counter that counts the number of 1s from the electrical signal converted by the optical device and outputs a HIGH signal when the counted value is greater than 1;
a second counter for counting the number of zeros from the electrical signal converted by the optical device and outputting a high signal when the counted value is greater than one;
and an AND gate for determining the presence of an optical signal based on output signals from the first counter and the second counter;
the first counter and the second counter are reset every 32 times the data rate by a reference clock;
Digital optical signal detection circuit.

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