in process flow 311 corresponding to determining the tdm 1 signal state and the dashed lines in process flow 312 corresponding to determining the tdm 2 signal state moreover the process flows 310 312 are shown in parallel to illustrate the desired concurrency of the three process flows executed by the controller 150 in the first portion 303 it is understood however that the process flows may be executed serially or the steps in the various process flows may be interleaved beginning with step 313 and similarly with steps 323 and 333 the controller 150 retrieves the tracking flag and cofdm signal intensity data from demodulator 120 in step 314 if the tracking flag is set then in step 315 the cofdm signal state variable is set to u201c on u201d and control passes to step 325 fig3 b however if the tracking flag is clear i e not set then in step 316 if the extant cofdm signal state variable i e the signal state as determined from an immediately preceding analysis by controller 150 executing process flow 310 is set to u201c off u201d and the cofdm signal intensity is greater than a threshold value th 1 then in step 317 the cofdm signal state variable is set to u201c fading u201d indicating that the cofdm signal being received is fading in i e the signal is increasing in intensity.