System and method for an adaptive state machine to control signal filtering in a serial link

Abstract

A method for adaptively filtering a control signal in a serial link includes monitoring for a blanking interval in a video stream having an associated clock signal and monitoring for an occurrence of a V SNYC signal once the blanking interval has started. A control signal is initially detected wherein the control signal occurs subsequent to the occurrence of the V SNYC signal. A set of properties of the control signal are recorded and a set of filter parameters are adjusted for detecting the control signal in a next blanking period based on the set of properties of the control signal.

1 . A receiver for adaptively filtering a control signal in a serial link, the receiver comprising: 
 a plurality of input ports adapted to receive a plurality of data signals and a clock signal on a plurality of differential pairs at said input ports;    a demodulator responsive to the plurality of data signals and the clock signal and operative to develop a control signal, a plurality of synchronization signals, and the clock signal;    a content protection state machine responsive to the plurality of synchronization signals, a filtered control signal, and the clock signal;    a filter responsive to the control signal and a filter parameter signal and operative to develop the filtered control; and    a control machine responsive to the control signal and operative to develop the filter parameter signal, wherein the filter parameter signal is updated based on a set of characteristics of the control signal.    
   
   
       2 . A receiver as in  claim 1 , wherein the content protection state machine is operative to develop an authentication signal.  
   
   
       3 . A receiver as in  claim 1 , wherein the demodulator is operative to develop the plurality of data signals.  
   
   
       4 . A receiver as in  claim 1 , wherein the plurality of data signals and a clock signal on a plurality of differential pairs are received from an external transmitter responsive to the authentication signal and operative to develop the plurality of data signals and the clock signal on the plurality of differential pairs.  
   
   
       5 . A receiver as in  claim 1 , further comprising the transmitter.  
   
   
       6 . A receiver as in  claim 1 , further comprising the transmitter in communication with the receiver.  
   
   
       7 . A method for adaptively filtering a control signal in a serial link, the method comprising: 
 receiving a plurality of data signals and a clock signal on a plurality of differential pairs;    generating a control signal, a plurality of synchronization signals, and the clock signal;    generating an authentication signal using a content protection state machine responsive to the plurality of synchronization signals, a filtered control signal, and the clock signal;    generating a filtered control signal from the control signal and a filter parameter signal; and    generating a filtered parameter signal from the control signal, wherein the filter parameter signal is updated based on a set of characteristics of the control signal.    
   
   
       8 . A method as is  claim 7 , wherein the generating of the authentication signal is achieved using a content protection state machine implemented procedure.  
   
   
       9 . A method as is  claim 7 , wherein the generating of the filtered parameter signal is achieved using a control machine implemented procedure.  
   
   
       10 . A method as is  claim 7 , wherein the generating a control signal, a plurality of synchronization signals, and the clock signal is achieved at least in part by demodulating at least one or the plurality of data signals and the clock signal to develop the control signal, the plurality of synchronization signals, and the clock signal.  
   
   
       11 . A method as is  claim 7 , wherein the generating or a filtered control signal is achieved at least in part by filtering to develop the filtered control signal from the control signal and the filter parameter signal.  
   
   
       12 . A method as is  claim 7 , wherein: 
 the generating of the authentication signal is achieved using a content protection state machine implemented procedure;    the generating of the filtered parameter signal is achieved using a control machine implemented procedure;    the generating of the control signal, the plurality of synchronization signals, and the clock signal is achieved at least in part by demodulating at least one or the plurality of data signals and the clock signal to develop the control signal, the plurality of synchronization signals, and the clock signal; and    the generating or a filtered control signal is achieved at least in part by filtering to develop the filtered control signal from the control signal and the filter parameter signal.    
   
   
       13 . A transmitter for use in a serial link, the transmitter being responsive to an authentication signal and operative to generate a plurality of data signals and a clock signal on a plurality of differential pairs; and, means for communicating at least some of the a plurality of data signals and a clock signal to a receiver.