US 8,427,242 B2 · Ultra wideband on-chip pulse generator

Abstract

A method for generating an UWB pulses based on LC oscillator topology. Fast turn on of the oscillator is achieved by creating large asymmetry in a normally symmetrical topology which is used in a typical differential type oscillator. One method for achieving large asymmetry is activating one branch of a differential pair of branches for a short duration before activating both branches in a normal operation. The bandwidth of the pulse is controlled by modifying the duration of the oscillator activation. Fast turn on and turn off is essential for high bandwidth generation. The method is adaptable for generating binary phase shift keying (BPSK) modulation. Selecting the activated branch of a fully symmetrical topology controls the output phase and creates two possibilities which differ exactly by 180 degrees. In a preferred embodiment, all the pulse generator components are on-clip leading to a low cost solution. The circuit can generate high power pulses directly on a load. It is also an option to add an amplifier to drive the output and separate the load from the oscillator. This method generate high power, stable pulses under varying practical conditions like process changes, VDD changes and temperature changes.

Claims26

Dependent claims

A method for producing a high power Radio Frequency pulse for a very short duration, the method comprising:

(a) providing an oscillator having a symmetric topology;
(b) activating a first branch of a differential pair of branches of said symmetric topology for a short duration by switching a connection to ground so as to break circuit symmetry and thereby create a large asymmetry in initial voltages;
(c) activating a second branch of said symmetric topology by switching a connection to ground to begin oscillations;
and
(d) deactivating at least one of said first branch and said second branch to terminate oscillations,
wherein the very short duration of the Radio Frequency pulse is approximately 1 nanosecond.

3 more elements

A high power Radio Frequency pulse generator for generating a high power Radio Frequency pulse for a very short duration, the pulse generator comprising:

(a) an oscillator having a symmetric topology;
(b) at least a first switch configured in a first branch of a differential pair of branches of said symmetric topology;
and
(c) at least a second switch configured in a second branch of said differential pair of branches of said symmetric topology;
wherein closure of one of said first and said second switches breaks a circuit symmetry of said symmetric topology so as to create an asymmetry in initial voltages of said differential pair of branches and subsequent closure of another of said first and said second switches begins oscillations and opening of at least one of said first and said second switches terminates oscillations;
wherein said oscillator has a cross coupled oscillator topology;
and
wherein said first branch of said cross coupled topology includes at least a first transistor and said second branch of said cross coupled topology includes at least a second transistor and said first switch connects a gate of said first transistor to a drain of said second transistor and said second switch connects a gate of said second transistor to a drain of said first transistor and a third switch connects said gate of said first transistor to ground and a fourth switch connects said gate of said second transistor to ground.

5 more elements

Dependencies are inferred from the claim text.

Ultra wideband on-chip pulse generator

Life of this patent

Ultra wideband on-chip pulse generator

Life of this patent

Abstract

Claims26