Clock recovery and detection of rapid phase transients
Granted: April 15, 2003
Patent Number:
6549604
Systems and methods are described for clock recovery and detection of rapid phase transients. An apparatus includes: a numerically controlled oscillator; a phase detector coupled to the numerically controlled oscillator; and a multiplexer coupled to the phase detector and the numerically controlled oscillator, wherein a) the phase detector sets a state variable indicator to either i) a high value if an output phase of the numerically controlled oscillator lags an incoming signal phase,…
Global positioning system receiver capable of functioning in the presence of interference
Granted: January 28, 2003
Patent Number:
6512803
Systems and methods are described for a GPS receiver capable of functioning in the presence of interference. A method includes detecting an interfering signal including: tuning a band pass filter over a frequency range; and at each of a plurality of incremental frequencies: computing a set of band pass filter coefficients; sending the set of band pass filter coefficients to a digital filter; repeatedly transforming an analog-to-digital converter output having a quantization level in…
Multi-link segmentation and reassembly for bonding multiple PVC's in an inverse multiplexing arrangement
Granted: December 3, 2002
Patent Number:
6490296
Systems and methods are described for multi-link segmentation and reassembly for bonging multiple virtual circuits in an inverse multiplexing arrangement. A method includes: generating a plurality of multilink segmentation and reassembly sublayer cells at a first location; distributing the plurality of multilink segmentation and reassembly sublayer cells across a plurality of virtual circuits; transmitting the plurality of multilink segmentation and reassembly sublayer cells to a second…
Positioning systems
Granted: September 4, 2001
Patent Number:
6285315
A satellite-based positioning system includes at least one mobile station (11) and a terrestrial station (10), which may be a cellular telephone base station and is arranged to receive ephemeris data from each in-view positioning satellite. The ephemeris data is processed in a processor (14) to provide processed data which defines the satellite orbit in Cartesian form. Processed data is transmitted over a short message service channel to each mobile receiver (11), which includes also a…
Phase detector
Granted: June 19, 2001
Patent Number:
6249750
Apparatus for measuring the phase of a predetermined incoming data sequence comprising, sampling means operable under control of a sampling clock to sample the incoming sequence at a frequency not equal to an integer multiple or divisor of the data rate of the sequence, test means operable to record a plurality of the samples in a time-ordered sequence, reference means operable to store a copy of at least a portion of the predetermined digital data sequence, comparison means operable to…
Dielectric-loaded antenna
Granted: February 6, 2001
Patent Number:
6184845
A dielectric-loaded loop antenna for operation at frequencies above 200 MHz has an elongate cylindrical core with a relative dielectric constant greater than 5, a pair of co-extensive helical antenna elements, a coaxial feeder structure extending through the core from a proximal end to a distal end where it is coupled to the antenna elements, and a balun formed on the core cylindrical surface and connected to the feeder structure at the proximal end of the core. Each helical antenna…
Antenna
Granted: January 30, 2001
Patent Number:
6181297
An antenna for use at UHF and upwards has a cylindrical ceramic core with a relative dielectric constant of at least 5. A three-dimensional radiating element structure, consisting of helical antenna elements on the cylindrical surface of the core and connecting radial elements on a distal end face of the core, is formed by conductor tracks plated directly on the core surfaces. At the distal end face the elements are connected to an axially located feed structure in a plated axial passage…
Thermo-electric cooled oven controlled crystal oscillator
Granted: December 26, 2000
Patent Number:
6166608
The present invention is a stabilized oscillator system comprising an oven controlled crystal oscillator positioned inside an insulated housing. Within the insulated housing, there is a cold plate in thermal contact with the oven controlled crystal oscillator and a thermo-electric cooler in contact with the cold plate. A heat sink external to the insulated housing is in thermal contact with the thermo-electric cooler. The thermo-electric cooler pumps heat into or out of the oven…
Mobile position determination with error correction utilizing cellular networks
Granted: October 3, 2000
Patent Number:
6128501
A position determining system takes the form of a cellular radio system including at least one base station having a base station satellite receiver (6) and a mobile unit including a cellular mobile station (50) coupled to a local satellite receiver (58). The base station transmits base station satellite data via a cellular radio link to the mobile unit, the data including data representing a carrier phase measurement derived from a satellite signal (70) received by the base station…
Synchronization of TDMA cell sites
Granted: September 26, 2000
Patent Number:
6125125
New methods for synchronizing previously unsynchronized BTS's of time division multiple access cellular networks are disclosed. Timing information that is readily available throughout the network is used to determine for each BTS when information representing a particular event is transmitted relative to the timing information. The time differences that are detected are used for steering the clock of each BTS to have the next or some other subsequent event transmitted at the same time.
Antenna system for radio signals in at least two spaced-apart frequency bands
Granted: October 5, 1999
Patent Number:
5963180
In an antenna system for radio signals in at least two spaced-apart frequency bands above 200 MHz, a quadrifilar helical antenna having an elongate dielectric core with a relative dielectric constant greater than 5 has a conductive sleeve surrounding a proximal part of the core and a longitudinal feeder structure extending through the core to a connection with the helical antenna elements at a distal end of the core. The antenna is operated in an upper frequency band in which it exhibits…
Dielectrically loaded antenna and a handheld radio communication unit including such an antenna
Granted: August 31, 1999
Patent Number:
5945963
A miniature antenna for operation at frequencies in excess of 200 MHz has a ceramic core in the form of a cylindrical rod having a relative dielectric constant greater than 5. Plated on the outer surfaces of the core is an antenna element structure comprising a single pair of oppositely disposed helical elements having a common central axis coincident with the central axis of the core. At a distal end of the antenna, they are connected to a coaxial feeder structure passing axially…
Multiple input frequency locked loop
Granted: August 24, 1999
Patent Number:
5943381
A dual locked loop is disclosed comparing preferably a GPS signal with an E1 signal and the E1 signal with the output of the loop. The GPS signal is low pass filtered to provide a low pass filtered GPS versus E1 signal that is used as a calibration for a closed loop having a second low pass filter for filtering the comparisons of the E1 and the output signal. By appropriately selecting the filter parameters, the output stability can track the stability of the local oscillator driving the…
Antenna
Granted: January 12, 1999
Patent Number:
5859621
An antenna for use at frequencies of 200 MHz and upwards has a cylindrical ceramic core with a relative dielectric constant of at least 5, and pairs of helical elements extending from a feed point at one end of the core to the rim of a conductive sleeve adjacent the other end of the core, the sleeve acting as a trap for isolating from ground currents circulating in the helical elements. To yield helical elements of different lengths, the sleeve rim follows a locus which deviates from a…
Superheterodyne radio receiver
Granted: November 3, 1998
Patent Number:
5832375
A satellite navigation receiver uses common dual-conversion superheterodyne and frequency synthesiser circuitry for receiving signals from both the GPS and the GLONASS satellite navigation systems. Successive first and second frequency down-converters in the receiver chain are fed by first and second local oscillator signals which are both variable in frequency such that the frequency of the first local oscillator signal is an integral multiple (preferably 8) of the second local…
Distribution of synchronization in a synchronous optical environment
Granted: October 27, 1998
Patent Number:
5828670
Apparatus and methods for distributing synchronization throughout a network is disclosed. The distribution of the synchronization is through the use of generating a reference timing signal, and by counting the line clock pulses between the start of a frame and the timing reference signal pulse at a first office and that count is then encoded and transmitted to the next office. At the next office, the transmitted count is decoded and used for regenerating synchronization by counting a…
DSP implementation of a cellular base station receiver
Granted: June 9, 1998
Patent Number:
5764704
Demodulating FM signals using digital signal processing extracts a carrier signal from digitized channel signals, multiplies the digital channel signal with this extracted carrier signal, and further filters out the carrier signal to produce the demodulated signal. The DSP technique first down converts a group of channels to baseband which are then processed through an A/D converter to produce a digitized composite signal. A bank of bandpass filters, typically based on FFT processors,…
Multiple input frequency locked loop
Granted: May 12, 1998
Patent Number:
5751777
A dual locked loop is disclosed comparing preferably a GPS signal with an E1 signal and the E1 signal with the output of the loop. The GPS signal is low pass filtered to provide a low pass filtered GPS versus E1 signal that is used as a calibration for a closed loop having a second low pass filter for filtering the comparisons of the E1 and the output signal. By appropriately selecting the filter parameters, the output stability can track the stability of the local oscillator driving the…
Digital phase detector employing a digitally controllable delay line
Granted: July 8, 1997
Patent Number:
5646519
A digital phase detector composed of: a digitally controllable signal delay device having a signal input, a signal output and a control input, the delay device being operative for conducting a signal from the signal input to the signal output with a time delay having a duration determined by a control signal supplied to the control input, the signal input being connected to receive either an input signal or a digital local clock signal; a phase relation detector connected to receive a…
Encoding system for distribution of synchronization
Granted: June 10, 1997
Patent Number:
5638379
Apparatus and methods for distributing synchronization throughout a network is disclosed. The distribution of the synchronization is through the use of generating a reference timing signal, and by counting the line clock pulses between the start of a frame and the timing reference signal pulse at a first office and that count is then encoded and transmitted to the next office. At the next office, the transmitted count is decoded and used for regenerating synchronization by counting a…
