Avago Technologies Ecbu IP (singapore) Pte. Ltd.

Mei Yee Ng

Gim Eng Chew

Chung Min Thor

Aik Yean Tang

Disclosed are various embodiments of pulse generation and automatic gain control ('AGC') circuits and corresponding methods that are especially well suited for use in motion encoding systems. Analog output signals provided by a motion encoder serve as inputs to the pulse generation circuit, where peaks, valleys and/or crosspoints corresponding to such analog signals are first detected and then employed to generate output pulses corresponding thereto. These output pulses are next provided to an AGC circuit as self-generated clock signals which control the time windows over which the analog signals of the motion encoder are sampled and processed by the AGC circuit so as to adjust the gains applied to such analog signals.

Automatic gain control for motion encoder signals

According to one embodiment, there is provided a device and method for correcting code wheel misalignment which employs upper and lower code wheel misalignment photodetectors positioned above and below at least first and second motion detection photodetectors. According to other embodiments, there are provided a device and method for automatically setting the gain of an output circuit in an optical encoder. Still further embodiments of optical encoders combine the code wheel misalignment and automatic gain control features of the invention.

Optical encoder with code wheel misalignment detection and automatic gain control

Disclosed are various embodiments of interpolation circuits for use in conjunction with motion encoders. The analog output signals provided by incremental or absolute motion encoders are provided to an interpolation circuit, which is capable of providing high interpolation factor output signals having high timing accuracy. Problems with noise spikes common to zero-hysteresis comparators typically employed in interpolation circuits are eliminated, as are problems with time delays differing between comparators that do feature hysteresis. The disclosed interpolation circuits may be implemented using CMOS processes without undue effort.

Interpolation accuracy improvement in motion encoder systems, devices and methods

An optical receiver having a photodetector, a variable gain amplifier, and a gain control circuit is disclosed. The photodetector generates a photodetector output signal related to an intensity of light received by the photodetector, the photodetector output signal being characterized by a peak-to-peak signal value. The variable gain amplifier amplifies the photodetector output signal to generate a receiver output signal that is coupled to an external device, the variable gain amplifier having a gain that is determined by a gain control signal. The gain control circuit receives the receiver output signal and generates the gain control signal therefrom. The gain control signal causes the gain of the variable gain amplifier to decrease as a function of the peak-to-peak signal value to reduce changes in the output signal amplitude as a function of the input light signal amplitude.

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Perak, Malaysia

Mei Yee Ng