Hi, All: I experienced a problem with the plotter class of using the Ptolemy II. Can anyone give some help and suggestion. The program is to simulate a signal inverter gate. The inverter class is extended from TypedAtomicActor. It has two DEIOPorts. The initialize() and postfire() method are not included in the class. It receives the token and sends out the new token with a fixed delay. The main testbench program is a DEapplet with one clock feeding the input of the inverter and the outputs of the clock and the inverter linked to two separate TimedPlotter. The period of the clock is 1. The problem is that the period of the inverter output is 2. I used the print command to send the time and output token to the console. And it shows period of 1 . Thanks for any help. ---------------------------------------------------------------------------- Posted to the ptolemy-hackers mailing list. Please send administrative mail for this list to: [EMAIL PROTECTED]