sentences:  Tikker
  
  A tikker, alternately spelled "ticker", was a vibrating interrupter used in early wireless telegraphy radio receivers such as crystal radio receivers in order to receive continuous wave (CW) radiotelegraphy signals.In the early years of the 20th century, before modern AM or FM radio transmission was developed, radio transmitters communicated information by radiotelegraphy; the transmitter was switched off and on by the operator with a telegraph key, producing pulses of radio waves, to spell out text messages in Morse code.