US 6,983,299 B1
Programmable digital filter implementation for loss-of-signal detection for serial communications applications
Christopher D. Paulson, Fort Collins, Colo. (US); and Steven A. Schauer, Loveland, Colo. (US)
Assigned to LSI Logic Corporation, Milpitas, Calif. (US)
Filed on Aug. 28, 2001, as Appl. No. 9/940,754.
Int. Cl. G06F 17/10 (2006.01)
U.S. Cl. 708—300 20 Claims
OG exemplary drawing
 
1. An apparatus comprising:
a sample circuit configured to (i) detect a state of an input signal and (ii) present a plurality of intermediate signals each representative of said state of said input signal during a plurality of clock cycles; and
a selection circuit configured to present a filtered signal in response to (i) a selected number of said intermediate signals having a lost state and (ii) a multi-bit selection signal representing a filtering value, wherein said filtered signal indicates said input signal has been lost when said selected number of lost states is greater than said filtering value.