Koninklijke Philips Corporation N.V.

Vlsi Technology, Inc.

Nxp B.v.

Remi Butaud

Bernard Ginetti

A method of producing a clock signal with reduced electromagnetic interference spectral components includes providing a first clock signal; producing a second clock signal by delaying the first clock signal; and generating a jittered clock signal by switching between the first clock signal and the second clock signal at times selected responsive to a random number generator. A GSM phone comprises a clock configured to produce a first clock signal; a delay element coupled to the clock to produce a second clock signal by delaying the first clock signal; a multiplexer coupled to the clock and to the delay element to select between the clock and the delay element; a random number generator coupled to the multiplexer wherein the multiplexer generates a jittered clock signal by switching between the first clock signal and the second clock signal responsive to the random number generator; and a plurality of GSM phone components respectively coupled to the multiplexer to use the jittered clock signal as an input clock for the component.

Clock circuit, GSM phone, and methods of reducing electromagnetic interference

The present invention, generally speaking, provides compact ROM layouts for trace or via-programmable (e.g., metal programmable) using transistor stacks. A number of field effect transistors (for example, eight) are coupled in series. For a particular transistor, a logic zero is programmed by forming a metal trace between the source and drain of the transistor. To read out the value of a particular bit, a logic zero is applied to the gate of the corresponding transistor. Logic ones are applied to the gates of the remaining transistors in the stack. A logic one precharge signal is applied to the top and bottom of the stack. A logic zero is then applied to the bottom of the stack. The logic zero reaches a sense amplifier coupled to the top of the transistor stack only if there is a short circuit across the transistor being read, indicating a logic zero bit value. Otherwise, the precharged logic one condition remains. Transistor stacks may be paired in a similar manner as individual transistors in conventional layouts. A very efficient ROM layout results.

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Valbonne, France

Remi Butaud