Pulse or digital communications – Pulse code modulation – Noise or distortion reduction
Patent
1998-02-26
2000-12-12
Chin, Stephen
Pulse or digital communications
Pulse code modulation
Noise or distortion reduction
375257, 375377, 333 19, 333177, 333178, H04B 1700
Patent
active
061608513
ABSTRACT:
A calibration circuit adjusts a differential output voltage from a line driver circuit when the differential output voltage falls outside a specified tolerance range. The calibration circuit includes a sample and hold circuit which samples the differential output voltage and holds a representative signal. A comparator compares the held signal with a reference voltage signal. When the held signal is greater than the reference voltage signal the comparator outputs a LOW signal and when the held signal is less than the reference voltage signal the comparator outputs a HIGH signal. The comparator output signal is stored in a memory circuit of a control logic. The control logic instructs an up/down counter to increment when the comparator output is LOW and to decrement when the comparator output is HIGH. A calibration current source sinks a unit of calibration current when the comparator output is LOW and sources a unit of calibration current when the comparator output is HIGH. The calibration current is added to an input current to calibrate the differential output voltage towards the specified tolerance range. In a next cycle of the calibration sequence, if a new comparator output signal is different from that stored in the memory circuit, the calibration sequence ceases. However, if the new comparator output signal is the same as that stored in the memory circuit the calibration sequence continues.
REFERENCES:
patent: 5315597 (1994-05-01), Yang et al.
patent: 5541957 (1996-07-01), Lau
patent: 5764394 (1998-07-01), Yamazaki et al.
patent: 5784573 (1998-07-01), Szczepanek et al.
Brown Gary A.
Mohan Jitendra
Chin Stephen
Ha Dac V.
National Semiconductor Corporation
LandOfFree
Line driver calibration circuit does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Line driver calibration circuit, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Line driver calibration circuit will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-224456