Koninklijke Philips Corporation N.V.

Philips Electronics North America Corporation

Broadband Royalty Corporation

Koninklijke Philips Electronics N.v.

Philips Intellectual Property & Standards Gmbh

Marcel F C Schemmann

Aalbert Stek

Holger Joachim Moench

Alexander Marc Van Der Lee

Silvia Maria Booij

Venkatesh G Mutalik

Pieter Hoeven

Roger King

Zhijian Sun

Lee Chappell

Stefan Schwan

Klaus P Werner

Carsten Heinks

Philipp H Gerlach

Mark Carpaij

Meng Han

Armand Pruijmboom

A cable television (CATV) distribution system, and a method of forming and using the CATV distribution system. In a first embodiment, a narrowcast optical signal is generated by an uncooled laser and converted by a receiver into a narrowcast electrical signal. In a second embodiment, a narrowcast optical signal generated by an uncooled laser is combined with a broadcast optical signal by an optical coupler at a hub of the CATV distribution system to generate a composite optical signal, which at a CATV node is: split into the broadcast and narrowcast optical components, respectively converted into broadcast and narrowcast electrical components, and combined into a composite electrical signal. In a third embodiment, a narrowcast optical signal is generated by an uncooled laser and then combined with the broadcast optical signal by a single receiver.

Uncooled laser generation of narrowcast CATV signal

A switching power supply that can operate in critical conduction mode as self-oscillating power supply (SOP) during moderate load, and in discontinuous conduction mode (DCM) under the control of a pulse-width modulated signal under small load, whereby the power consumption of the supply is decreases continuously as the load is decreased. A frequency modulated self-oscillating switching power supply (FMSOP) having a power switch, the switch being held OFF, after a zero-current detector detects that an output current falls to zero, until allowed to turn ON after a pulse having a load-modulated width that corresponds to the load. The FMSOP operates with a switch controller that may include a flip-flop to latch the detector's signal, a load-modulated pulse generator, and a combinatorial logic gate to combine the pulse and the latched signal.

Frequency modulated self-oscillating switching power supply

A laser transmitter bias circuit for a laser diode transmitter, for use in a optical transmission system, e.g. in commercial CATV systems. The laser transmitter bias circuit reduces power consumption and heat dissipation by eliminating the conventional need for a distinct constant DC current supply for biasing the laser diode. Radio frequency (RF) circuitry, e.g., a radio frequency amplifier (e.g., a Hybrid Amplifier), connected in series to the laser diode supplies both a DC bias-current (I ) and an RF drive-current (I ) through the laser diode. The DC bias current through the laser diode in turn powers (and/or biases) the radio frequency amplifier and, optionally, other radio frequency circuitry. An optional diode-bypass current (I ) path may be connected in parallel with the laser diode, and in series with the radio frequency amplifier to control bias current.

Laser transmitter bias circuit

A method and structure for generation of signal distortion. In a first embodiment, a first signal distortion generator (SDG) receives a pair of balanced input currents &plus;X and &minus;X, each having a same angular frequency &ohgr;. The first SDG generates a pair of output currents &plus;X&plus;&Dgr;X and &minus;X&plus;&Dgr;X , wherein &Dgr;X &minus;&Dgr;X &equals;G X &plus;G X . G and G are each independent of X, and at least one of G and G is nonzero. In a second embodiment, a second SDG receives an unbalanced input current P having an angular frequency &ohgr;. The second SDG generates an output current U of a form P&plus;(&agr;P&plus;&bgr;P &plus;&ggr;P )/2. &agr;, &bgr;, and &ggr; are each nonzero and each independent of P. The second SDG includes a distortion generating circuit path that has an input impedance ratio of at least 5 and an output impedance ratio of at least 5.

Distortion generation in balanced and unbalanced signals

The present invention relates generally to an amplifier such as that with the radio frequency (RF) spectrum having a nonlinear feedback loop to cancel out distortions in the input signal, and method therefor.

Nonlinear feedback linearizer

A method and apparatus for controlling and stabilizing laser wavelengths in a dense wavelength division multiplexer (DWDM) transmission system. The lasers in the transmission system are each modulated in a known manner by a data signal. In addition, the lasers are each modulated by a plurality of test signals each having a predetermined frequency. At the optical receiver, a frequency analyzer examiners the frequency test signals for distortions and/or changes in amplitude. Any distortions and/or changes in amplitude of the frequency test signals indicate a change in the wavelength of a corresponding laser. A control signal may be returned to the laser controller of each laser to regulate the laser wavelength. A fault signal may be generated indicating that the wavelength of a laser has changed, drifted, etc., more an acceptable amount.

Laser wavelength control in an optical communication system

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Echt, Netherlands

Marcel F C Schemmann