Cycle-by-cycle synchronous waveform shaping circuits based on time-domain superpostion and convolution

• US 20020196865A1
• Filed: 03/08/2002
• Published: 12/26/2002
• Est. Priority Date: 06/25/2001
• Status: Abandoned Application

• Current Assignee: Singapore The National University of
• Original Assignee: National University of Singapore
• Inventors: Soh, Wei Kwek
• Application Number:
  US10/095,656
• Publication Number:
  US 20020196865A1
• Time in Patent Office: Days
• US Class Current: 375/303
• CPC Class Codes: H03C 3/00 Angle modulation H03C5/00, H03C7/00 take precedence

Abstract

Cycle-by-cycle synchronous waveform shaping is provided for by filtering and combining of square and/or impulse shaped signals. Specifically, a plurality of first square shaped signals is generated and filtered using at least one first filter to produce at least one filtered signal. A plurality of second square shaped signals is generated and filtered using at least one second filter to produce at least one second filtered signal. The at least one first and at least one second filtered signals are combined to produce a continuous shaped waveform having a characteristic shape within each of a plurality of data periods defining a data rate. Alternatively, at least one impulse signal having a plurality of sinusoidal impulses each comprising a positive impulse and a negative impulse is generated. The at least one impulse signal is filtered using at least one filter to produce the continuous shaped waveform.

Claims

1. A method for generating a continuous shaped waveform for transmission in a communication system, the method comprising:

generating a plurality of first square shaped signals;

filtering said first square shaped signals to produce at least one filtered signal;

generating a plurality of second square shaped signals;

filtering said second square shaped signals to produce at least one second filtered signal; and

combining said at least one first and at least one second filtered signals to produce said continuous shaped waveform, said continuous shaped waveform having a characteristic shape within each of a plurality of data periods defining a data rate.

2. The method of claim 1 wherein said first filtered signals significantly cancel one another in at least one of said data periods.

3. The method of claim 2 wherein said second filtered signals significantly add to one another in said at least one of said data periods.

4. The method of claim 1 wherein said continuous shaped waveform is a Frequency Shift Keying (FSK) signal having at least a first frequency component and a second frequency component, wherein said first frequency component is based on said first square shaped signals, and wherein second frequency component is based on said second square shaped signals.

5. The method of claim 1 wherein said first and second square shaped signals are digital signals.

6. The method of claim 1 wherein said first and second square shaped signals are synchronous signals.

7. The method of claim 1 further comprising a step of removing DC component from said first and second square shaped signals.

8. The method of claim 1 further comprising the steps of:

before said step for filtering said first square shaped signals, combining said first square shaped signals; and

before said step for filtering said second square shaped signals, combining said second square shaped signals.

9. The method of claim 8 wherein said first square shaped signals significantly cancel one another in at least one of said data periods.

10. The method of claim 9 wherein said second square shaped signals significantly add to one another in said at least one of said data periods.

11. The method of claim 1 wherein said at least one first filtered signal and said at least one second filtered signal are combined differentially.

12. The method of claim 8 wherein said first square shaped signals are combined differentially and said second square shaped signals are combined differentially.

13. The method of claim 1 wherein said filtering said first square shaped signals includes performing one of:

a Gaussian-type filtering, a Bessel-type filtering, and a Butterworth-type filtering operation.

14. The method of claim 1 wherein said continuous shaped waveform is a Phase Shift Keying (PSK) signal.

15. The method of claim 14 wherein said PSK signal is a Binary Phase Shift Keying (BPSK) signal.

18. The method of claim 17 further comprising a step of combining said impulse signals before said filtering step.

19. The method of claim 17 further comprising a step of combining said impulse signals after said filtering step.

24. The method of claim 17 wherein said filtering in accordance with one of:

a Gaussian filter, a Bessel filter, and a Butterworth filter.

25. The method of claim 17 wherein said continuous shaped waveform is a Phase Shift Keying (PSK) signal.

27. The method of claim 17 wherein said continuous shaped waveform is a Frequency Shift Keying (FSK) signal.

16. A system for generating a continuous shaped waveform suitable for transmission in a communication system, the system comprising:

means for generating a plurality of first pulses;

means for filtering said first pulses to produce at least one filtered signal;

means for generating a plurality of second pulses;

means for filtering said second pulses to produce at least one second filtered signal; and

means for combining said at least one first and at least one second filtered signals to produce said continuous shaped waveform, said waveform having a characteristic shape within each of a plurality of data periods defining a data rate.

17. A method for generating a continuous shaped waveform suitable for transmission in a communication system, the method comprising:

generating at least one impulse signal having a plurality of sinusoidal impulses, each said sinusoidal impulse comprising a positive impulse and a negative impulse; and

filtering said at least one impulse signal to produce said continuous shaped waveform, said waveform having a characteristic shape within each of a plurality of data periods defining a data rate.

20. The method of 17 wherein at least one of said sinusoidal impulses is generated by differentially combining a square shaped signal with a delayed version of said square shaped signal.

21. The method of claim 20 wherein said square shaped signal is a digital signal.

22. The method of claim 20 wherein said square shaped signal is a synchronous signal.

26. The method of claim 27 wherein said PSK signal is a Binary Phase Shift Keying (BPSK) signal.

23. The method of 18 or 19 wherein said impulse signals are differentially combined.

28. A system for generating a continuous shaped waveform suitable for transmission in a communication system, the system comprising:

means for generating at least one impulse signal having a plurality of sinusoidal impulses, each said sinusoidal impulse comprising a positive impulse and a negative impulse; and

means for filtering said at least one impulse signal using at least one filter to produce said continuous shaped waveform, said waveform having a characteristic shape within each of a plurality of data periods defining a data rate.