Burst mode receiving apparatus having an offset compensating function and a data recovery method thereof

• US 6,694,105 B2
• Filed: 06/27/2002
• Issued: 02/17/2004
• Est. Priority Date: 06/27/2001
• Status: Expired due to Fees

• Current Assignee: Samsung Electronics Co. Ltd. (Samsung Group)
• Original Assignee: Samsung Electronics Co. Ltd. (Samsung Group)
• Inventors: Han, Gun-hee, Chae, Hyun-soo, Chang, Young-jun, Ryu, Hyun-surk
• Primary Examiner(s): MAI, SON LUU
• Application Number:
  US10/183,046
• Publication Number:
  US 20030012065A1
• Time in Patent Office: 600 Days
• Field of Search: 327/63, 327/72, 327/307, 375/317, 375/318, 375/345, 398/202, 398/208, 398/209
• US Class Current: 398/202
• CPC Class Codes: H04L 25/061 providing hard decisions only; arrangements for tracking or suppressing unwanted low frequency components, e.g. removal of dc offset removal of dc offset in coupling arrangements H04L25/029, H04L25/0296

Abstract

A burst mode receiving apparatus having an offset compensating function and a data recovery method thereof, including an intermediate value detector to detect and output an intermediate value of an input signal input from an outside source in response to a switching control signal; an amplifier to amplify and output a difference between the input signal and a reference value; an offset compensator to generate a compensation signal having a level varied corresponding to the amplified result input from the amplifier and a compensation control signal; a summing portion to add the compensation signal and the intermediate value to output the added result as the reference value to the amplifier; and a controller to generate the switching control signal and the compensation control signal corresponding to a result obtained by analyzing the amplified result input from the amplifier and a reset signal input from the outside source.

Claims

1. A burst mode receiving apparatus having an offset compensating function, comprising:

an intermediate value detector to detect an intermediate value between a maximum value and a minimum value of an input signal of an analog form discretely input from an outside source in response to a switching control signal, and output the detected intermediate value;

an amplifier to amplify a difference between the input signal and a reference value, and output the amplified result;

an offset compensator to generate a compensation signal having a level varied corresponding to the amplified result input from the amplifier and a compensation control signal;

a summing portion to add the, compensation signal input from the offset compensator and the intermediate value input from the intermediate value detector to output the added result as the reference value to the amplifier; and

a controller to generate the switching control signal and the compensation control signal corresponding to a result obtained by analyzing the amplified result input from the amplifier and a reset signal input from the outside source.

2. The burst mode receiving apparatus as claimed claim 1, wherein the burst mode receiving apparatus further comprises:

a bias signal generator to generate a bias signal in response to a bias control signal and to output the generated bias signal to the summing portion, the controller generates the bias control signal in response to the result obtained by analyzing the amplified result input from the amplifier, and the summing portion outputs the bias signal input to the bias signal generator as the reference value.

3. The burst mode receiving apparatus as claimed claim 1, wherein the offset compensator comprises:

a counter to perform a counting-up or counting-down operation in response to the amplified result input from the amplifier and a clock signal corresponding to the compensation control signal input from the controller to output the counted-up or counted-down result; and

a digital-to-analog converter to convert the counted-up or counted-down result input from the counter into the form of an analog signal and to output the resultant analog signal as the compensation signal to the summing portion.

4. The burst mode receiving apparatus as claimed in claim 1, wherein the offset compensator comprises:

a charge pump being enabled in response to a clock signal corresponding to the compensation control signal input from the controller, the charge pump for supplying or sinking an electric charge in response to the amplified result and for outputting a result obtained by supplying or sinking the electric charge as the compensation signal to the summing portion.

5. The burst mode receiving apparatus as claimed in claim 1, wherein the amplifier comprises:

a comparator having a very high gain including;

a positive (non-inverting) input terminal for receiving the input signal;

a negative (inverting) input terminal for receiving the reference value from the summing portion; and

an output terminal for outputting data recovered.

6. The burst mode receiving apparatus as claimed claim 1, wherein the intermediate value detector comprises:

a first capacitor, connected to a first node and a reference potential so that it is positioned between the first node and the reference potential, for charging the maximum value of the input signal;

a second capacitor, connected to a second node and a reference potential so that it is positioned between the second node and the reference potential, for charging the minimum value of the input signal;

a first switch connected between the input signal and the first node, the first switch being switched in response to a first switching signal;

a second switch connected between the input signal and the second node, the second switch being switched in response to a second switching signal;

a third switch connected between the input signal and the second node, the third switch being switched in response to a third switching signal;

a fourth switch connected to the first node and the second node so that it is positioned between the first node and the second node, the fourth switch being switched in response to a fourth switching signal; and

a fifth switch connected between the input signal and the first node, the fifth switch being switched in response to a fifth switching signal,

wherein the detected intermediate value is output through the second node, and the first, second, third, fourth and fifth switching signals correspond to the switching control signal.

7. The burst mode receiving apparatus as claimed claim 6, wherein the first through fifth switches are NMOS transistors.

8. The burst mode receiving apparatus as claimed claim 6, wherein the first through fifth switches are bipolar transistors.

9. The burst mode receiving apparatus as claimed in claim 6, wherein the intermediate value detector further comprises:

a first buffer positioned between the input signal and the fifth switch, the first buffer for buffering the input signal and outputting the buffered input signal to the fifth switch; and

a second buffer positioned between the input signal and one or more of the first switch, the second switch, and the third switch, the second buffer for buffering the input signal and outputting the buffered input signal to the one or more of the first switch, the second switch, and the third switch.

10. The burst mode receiving apparatus as claimed in claim 9, further comprising:

a third buffer for buffering the intermediate value prior to outputting the intermediate value to the summing portion.

11. The burst mode receiving apparatus as claimed claim 1, wherein the burst mode receiving apparatus further comprises:

a photodetector for dynamically detecting an optical signal in a packet unit, for converting the detected optical signal into an electric signal, and for outputting the converted electric signal; and

a preamplifier for amplifying the converted electric signal input from the photodetector and outputting the amplified result of the converted electric signal as the input signal to the intermediate value detector.

12. The burst mode receiving apparatus as claimed claim 1, wherein the summing portion comprises:

a current-voltage converter for adding the compensation signal of a current form and the intermediate value of a voltage form, for converting the added result into the reference value of a voltage form, and for outputting the reference value to the amplifier.

13. A data recovery method in a burst mode receiving apparatus, comprising:

(a) compensating for an offset of the burst mode receiving apparatus;

(b) preparing for reception of an input signal from an outside source;

(c) determining whether the input signal is given from the outside source, and returning to (b) if it is determined that the input signal is not given from the outside source;

(d) detecting an intermediate value between a maximum value and a minimum value of the input signal if it is determined that the input signal is given from the outside source;

(e) adding a compensation signal and the detected intermediate value to obtain a reference value;

(f) amplifying a difference between the input signal and the reference value and determining the amplified result as recovery data;

(g) determining if a reset signal is input, and returning to (f) if the reset signal is not input; and

(h) initializing the maximum value and the minimum value of the input signal if the reset signal is input.

14. The data recovery method as claimed in claim 13, wherein compensating for an offset of the burst mode receiving apparatus comprises:

(a1) determining whether a sign of the offset output from the amplifier is positive or negative when the input signal is not given from the outside source;

(a2) increasing a level of the reference value if it is determined that the sign of the offset is positive;

(a3) decreasing a level of the reference value if it is determined that the sign of the offset is negative; and

(a4) after increasing or decreasing a level of the reference value, determining whether the offset is in a form of a periodic square wave, returning to (a1) if the offset is not in the form of a periodic square wave, and proceeding to (b) if it is determined that the offset is in the form of a periodic square wave.

15. The data recovery method as claimed in claim 13, wherein preparing for reception of an input signal from an outside source comprises:

after compensating for an offset of the burst mode receiving apparatus, generating a bias signal and detecting the minimum value of the input signal,

wherein the offset output from the amplifier is maintained at a constant logic level when the bias signal is generated.

16. The data recovery method as claimed in claim 14, wherein increasing and decreasing a level of the reference value comprise:

performing a counting-up operation if it is determined that the sign of the offset is negative, and performing a counting-down operation if it is determined that the sign of the offset is positive;

converting the counted-up or counted-down result into the form of an analog signal and determining the resultant analog signal as the compensation signal; and

generating the reference value having a level inversely proportional to a level of the compensation signal.

17. The data recovery method as claimed in claim 13, wherein detecting an intermediate value comprises:

(d1) detecting the maximum value of the input signal and holding the minimum value detected at (d) if it is determined that the input signal is given from the outside source;

(d2) determining whether there is a lapse of a predetermined time period required to charge the maximum value of the input signal, and returning to (d1) if it is determined that there is not a lapse of the predetermined time period; and

(d3) detecting the intermediate value between the maximum value detected at (d1) and the held minimum value and proceeding to (e) if it is determined that there is a lapse of the predetermined time period.