pencil in vs squelch

pencil in

verb
  • to provisionally schedule 

  • to fill in or write in using pencil 

squelch

verb
  • To suppress the unwanted hiss or static between received transmissions by adjusting a threshold level for signal strength. 

  • To halt, stop, eliminate, stamp out, or put down, often suddenly or by force. 

  • To make a sucking, splashing noise as when walking on muddy ground. 

  • To walk or step through a substance such as mud. 

noun
  • A squelching sound. 

  • A kind of electronic beat or sound mainly used in acid house and related music genres. 

  • The suppression of the unwanted hiss or static between received transmissions by adjusting the gain of the receiver. 

How often have the words pencil in and squelch occurred in a corpus of books? (source: Google Ngram Viewer )