Resources Contact Us Home
Browse by: INVENTOR PATENT HOLDER PATENT NUMBER DATE
 
 
Pitch detection apparatus










Image Number 5 for United States Patent #4688464.

A pitch detector is disclosed that automatically recognizes the pitch of musical notes quickly and outputs the pitch information in a variety of formats. The detector employs a microprocessor that samples the signal from a musical instrument or voice at regular intervals using an analog-to-digital converter and then utilizes both amplitude and time information from the waveform to determine the fundamental period of the note, while rejecting the harmonic components. The microprocessor analyzes the waveform looking for peaks that are approximately equal in amplitude separated by opposite polarity peaks. The time intervals between the peaks must be approximately equal too. Timing information is measured using more than one point on the waveform to avoid inaccuracies caused by temporary distortions of the waveform. The timing points are chosen at points where the slope of the waveform is high for substantially optimal accuracy. To filter out erroneous readings caused by pitch detection during note transition or noise, additional processing of the data is performed to cause a second corroborating reading to be taken when a note transition that is uncommon musically is detected.








 
 
  Recently Added Patents
Estrogen receptor ligands
Touch-sensitive device and communication device
Low-coupling oxide media (LCOM)
Phase-change memory device having multiple diodes
Method and CTDevice for computer tomographic spiral scanning of a patient
Substrate and patterning device for use in metrology, metrology method and device manufacturing method
Apparatus and method for foreground detection
  Randomly Featured Patents
Method of and apparatus for electrical discharge machining with a vibrating wire electrode
Method of bracing end turns of an electric machine by means of a binding band; and device used therein
Sandbag filling stand
Container data center
Arrangement for the insertion of coils in a stator
Microphone with shock-resistant means
Polycarbonate with high extensional viscosity
Assist grip
Multiple operating frequencies in a processor
Pyrroles possessing insecticidal activity