Patents by Inventor John Duncan McNicol

John Duncan McNicol has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 7764732
    Abstract: Conventional adaptive equalizers often use the “sign/sign” algorithm as a low complexity means to adjust their tap weight coefficients by driving the correlation between its single-bit “error” and “data” signals to zero. This algorithm fails in the presence of strong residual intersymbol interference (ISI), since this ISI renders the “error” signal sufficiently inaccurate to mask the correlation between “data” and “error”. Failure manifests itself two-fold as an inability to achieve tap weight acquisition at startup, and an inability to track dynamic channel conditions. The invention described herein employs an adaptive estimator to compute the residual masking ISI terms that in turn control an adaptive error slicer to synthesize a modified single-bit “error” signal that remains correlated with the “data” signal.
    Type: Grant
    Filed: May 8, 2007
    Date of Patent: July 27, 2010
    Assignee: Applied Micro Circuits Corporation
    Inventors: Mark Edward Rollins, John Duncan McNicol
  • Patent number: 6363262
    Abstract: To accommodate for a release of uncleared spectrum in a wideband communication system (10) while improving isolation in a receiver (FIG. 4) between wideband carriers, a common intermediate frequency converter down-converts differing but relatively high frequency carriers, incident to the receiver, to corresponding differing but relatively low frequency carriers. Receiver chains (174-176) response to the plurality of relatively low frequency carriers each have a filter (140-144) arranged to isolate selected ones of the relatively low frequency carriers. In a radio frequency communication system having three or more frequency sequential carriers, the receiver chains (174-176) may include branches that have filters that further isolate carriers within the receiver by applying non-sequential carriers to the branches in each receiver chain.
    Type: Grant
    Filed: December 22, 1998
    Date of Patent: March 26, 2002
    Assignee: Northern Telecom Limited
    Inventor: John Duncan McNicol
  • Patent number: 6091298
    Abstract: This invention relates to high power linear amplifiers. A high power linear amplifier is disclosed for communications such as CDMA communication systems. Linear amplifiers as used in communication systems exhibit a linear characteristic where the amplifiers output power increases relative to an input power. After a certain input level, known as a gain saturation point, the amplifier then exhibits non-linear characteristics; the output power increases relatively little with respect to power input. This non-linear region is also known as the saturation region or the gain compression region.
    Type: Grant
    Filed: August 27, 1998
    Date of Patent: July 18, 2000
    Assignee: Nortel Networks Corporation
    Inventors: John Duncan McNicol, David Neal Wessel
  • Patent number: 5940454
    Abstract: A receiver for receiving a radio signal carrying digitally-encoded data has a plurality of diversity antennas, respectively coupled to inputs of a selector. A received signal selected by the selector is equalized by an adaptive equalizer and then demodulated to recover data, when possible. A quality metric dependent on the quality of the recovered data is generated. A switch controller responsive to the quality metric controls the selector. After the controller controls the selector to select a new antenna, it monitors the quality metric as the adaptive equalizer retrains and, if the quality metric does not exceed a predetermined threshold before a predetermined forward guard time expires, the controller causes the selector to select another antenna. The switch controller may also receive a signal level signal dependent on the level of the received signal.
    Type: Grant
    Filed: December 17, 1997
    Date of Patent: August 17, 1999
    Assignee: Nortel Networks Corporation
    Inventors: John Duncan McNicol, Edward Anthony Orchard
  • Patent number: 5770971
    Abstract: A control arrangement and method for controlling a gain and phase adjuster used for controlling the gain and phase of a compensation signal for compensating for the distortion produced by a power amplifier is disclosed. The control arrangement makes use of a reference signal, of known frequency, which is amplified along with the desired carrier signals. The reference signal component of the amplified signal is then isolated and a comparison is made, either with the actual reference signal, e.g., by a QAM demodulator, or alternatively with the known frequency of the reference signal, e.g., by a FM discriminator, in order to determine the differences in gain and in phase of the reference signal component of the amplified signal in comparison with the reference signal. For example, a QAM demodulator is used for producing a first difference signal indicative of the phase switch difference, and a second difference signal indicative of the gain switch difference.
    Type: Grant
    Filed: July 26, 1996
    Date of Patent: June 23, 1998
    Assignee: Northern Telecom Limited
    Inventor: John Duncan McNicol