Laser rangefinder receiver
AssigneeAnalog Modules, Inc.
InventorIan D. Crawford
Life of this patent
Estimating the term…
Abstract
In a laser rangefinder receiver, a return signal from a light-sensitive detector is passed through a high-pass filter, and is then processed in two separate circuit paths, a “signal” path and a “noise” path. The “signal” path employs a time-variable offset scheme to control receiver sensitivity. The “noise” path measures noise in the return signal, and maintain a noise-based threshold independent of the time-variable sensitivity of the “signal” path. No interstage coupling capacitors are employed, which contributes greatly to the receiver's quick saturation recovery.
Claims28
A laser rangefinder receiver, comprising:
- a light-sensitive detector;
- a high-pass element producing a detector signal;
- means for establishing a baseline for the detector signal;
- means for establishing a detection threshold, offset from the baseline by a threshold offset;
- and
- means for comparing the detector signal to the threshold;
- wherein:
- a noise detector establishes separate measurements of positive peaks and negative peaks;
- and
- a threshold offset is determined from a difference between the positive peak and negative peak measurements.
A laser rangefinder receiver, comprising:
- a light-sensitive detector;
- a high-pass element producing a detector signal;
- means for establishing a baseline for the detector signal;
- means for establishing a detection threshold, offset from the baseline by a threshold offset;
- and
- means for comparing the detector signal to the threshold;
- further comprising:
- means for varying detector sensitivity by initially decreasing detector sensitivity to a first level, then gradually increasing detector sensitivity to a second level after a trigger event.
A method of detecting laser pulses comprising:
- providing a light-sensitive detector for producing a first signal;
- filtering the first signal via a high-pass element to produce a detector signal;
- establishing a baseline for the detector signal;
- establishing a detection threshold, offset from the signal baseline;
- and
- comparing the detector signal to the threshold;
- further comprising:
- making separate measurements of positive and negative noise peaks;
- and
- determining the threshold offset from a difference between the positive peak and negative peak measurements.
A method of detecting laser pulses comprising:
- providing a light-sensitive detector for producing a first signal;
- filtering the first signal via a high-pass element to produce a detector signal;
- establishing a baseline for the detect or signal;
- establishing a detection threshold, offset from the signal baseline;
- and
- comparing the detector signal to the threshold;
- further comprising:
- varying detector sensitivity by initially decreasing detector sensitivity to a first level, then gradually increasing detector sensitivity to a second level after a trigger event.
Laser rangefinder receiver having an input for receiving a detector signal from a light-sensitive detector and an output, comprising:
- a high-pass filter connected to the output of the preamplifier, and having an output;
- a first amplifier having a first input, a second input and an output;
- a low-pass filter connected to the output of the first amplifier, and having an output;
- a noise detector having an input, a negative peak output, and a positive peak output;
- the output of the high-pass filter connected to the first input of the inverting amplifier and connected to the input of the noise detector;
- a combining element having an inverting input, a first non-inverting input, a second non-inverting input, a third non-inverting input, and an output;
- a trigger circuit for receiving a trigger pulse, and having an output;
- the output of the trigger circuit connected to the second input of the inverting amplifier;
- the negative peak output of the noise detector connected to the inverting input of the differential amplifier;
- the positive peak output of the noise detector connected to the first non-inverting input of the differential amplifier;
- the output of the low-pass filter connected to the second non-inverting input of the differential amplifier;
- the output of the trigger circuit connected to the third non-inverting input of the differential amplifier;
- a comparator having a positive input, a negative input and an output;
- the output of the differential amplifier connected to the positive input of the comparator;
- and
- the output of the inverting amplifier connected to the negative input of the comparator;
- wherein the output of the comparator comprises the output of the laser rangefinder receiver.
Dependencies are inferred from the claim text.