Miscellaneous active electrical nonlinear devices – circuits – and – Signal converting – shaping – or generating – Current driver
Reexamination Certificate
1999-12-30
2001-11-27
Wells, Kenneth B. (Department: 2816)
Miscellaneous active electrical nonlinear devices, circuits, and
Signal converting, shaping, or generating
Current driver
C327S065000
Reexamination Certificate
active
06323699
ABSTRACT:
FIELD OF INVENTION
The present invention relates to the field of signal processing in a computer system. More specifically, the present invention relates to single-ended and differential signals.
BACKGROUND OF THE INVENTION
Circuitry to send signals between components of a digital system, such as a computer system, are well-known. One known approach for sending signals between components of such digital systems is to use a single-ended signal. However, the signal speed, or frequency, of single-ended signals is limited to certain magnitudes depending on the technology before the signals are impaired by noise. A solution to the limitations of the single-ended signal is the differential signal which allows for faster signal speeds while reducing the effects of noise at such high speeds. Noise is reduced in the differential signal because the differential signal is based on the difference between two signals, such as a clock and an inverted clock. The combination of the two signals helps to cancel some of the noise. For instance, if the two signals are routed in close proximity, both signals are likely to experience the same noise. In which case, the difference between the two signals is likely to be largely unaffected by the noise.
A drawback of using differential signals is that components of older, slower systems that use single-ended signaling cannot be used in faster systems that use differential signals. Even if selected, faster differential input circuits cannot be driven by single-ended (slower) signals. Furthermore there is no interchangeability between the two approaches, and therefore, in order to facilitate the selection between a single-ended and a differential signal, receivers on printed circuit boards needed to be physically changed.
Another drawback of current differential input signal buffers is that an external reference voltage is required utilizing external resistors and capacitors. Utilizing external resistors and capacitors for the external reference voltage can cause variability of the resistors and the capacitors.
REFERENCES:
patent: 5166635 (1992-11-01), Shih
patent: 5798660 (1998-08-01), Cheng
patent: 5942922 (1999-08-01), Dinteman et al.
patent: 6028454 (2000-02-01), Elmasry et al.
patent: 6040731 (2000-03-01), Chen et al.
patent: 6137340 (2000-10-01), Goodel et al.
Blakely , Sokoloff, Taylor & Zafman LLP
Dinh Paul
Intel Corporation
Wells Kenneth B.
LandOfFree
Method and apparatus for variably providing an input signal does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method and apparatus for variably providing an input signal, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method and apparatus for variably providing an input signal will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2602926