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
RPM Controlled Wind Power Generation System
Device and method for quantizing and inverse quantizing LPC filters in a super-frame
Image processing apparatus, image display apparatus, and image processing method
Solid-state imaging apparatus and imaging system
System for targeted delivery of therapeutic agents
Management of computer-file sharing between at least two devices
System and method for stranded file opens during disk compression utility requests
  Randomly Featured Patents
Connector
Method for manufacturing inkjet recording head
Direct printing apparatus
Apparatus for stacking flat articles
Laterally pivoted weight training device
Thermoplastic resin composition
Adjustable formwork for concrete structures
Toy playhouse
Storage terminal, information processing apparatus, and information processing system
Automatic language selection for text input in messaging context