Telephone Interference Lab

Discussion in 'Homework Help' started by bham1307, Oct 2, 2008.

  1. bham1307

    Thread Starter New Member

    Oct 2, 2008
    Problem: You have been contacted by local telephone co. In one of their coverage areas, is an interference signal at 100KHz. It belongs to the coast gaurd and cannot be turned off. The interference signal is affecting the normal telephone carrier transmitted at 2KHz. They have also noticed a 6dB signal loss to all houses.

    Solution: Design a circuit that will filter the 100k signal, but pass the 2K signal. The test circuit should contain 2KHz oscillator & a 100KHz oscillator, a filter circuit, & a 6dB amplifier circuit. create a presentation to sell the phone company. Include circuit diagram, theory of operation, parts list, & pricing.
  2. bertus


    Apr 5, 2008
  3. JoeJester

    AAC Fanatic!

    Apr 26, 2005
    Did your instructor tell you the characteristics of the Coast Guard's Loran Signal operating at 100 kHz? It's not a CW signal by any stretch of the imagination, but I'm sure for your exercise, that is what he is proposing you to use.

    I'm sure this is just an intellectual exercise, because I didn't hear the CG's 100 kHz signal in the phone system when the 800 kW transmitting antenna was 40 feet away. :D

    To be fair, I did have some problems with the Loran Signal on the Fire Detection sensors, but I solved it by shunting the sensor with a suitablely low reactance.
    Last edited: Oct 3, 2008