Tektronix' (www.tektronix.com) Sentry digital content monitoring solution, part of the recent acquisition of Mixed Signals (www.mixedsignals.com), has been selected by Canadian cable operator Videotron. With its testing complete, Videotron plans to begin its initial deployments of Sentry in its master headend in Montreal this summer. Sentry will be used to monitor programs as they are aggregated at the headend and prior to distribution to markets served by the master headend.