A microphone converts the sound of the instrument into an electrical signal for application via an amplifier to an energy detector (e.g. integrator) and filter. The outputs are processed by a calculator comprising a microprocessor with random access memory for storage of the detected frequency and read-only memories for storage of standard-frequency notes and chords. Interface circuits are used for inputs from the detector and clock, and for outputs for a display (e.g. liq. crystal) device and audio-visual indicators performing the metronome function, for which the time intervals and measurements are selected by means of code wheels. The precise note nearest to the sound produced is displayed with indications of the magnitude and sign of the discrepancy. Musicians can thus check the tuning of an instrument or the accuracy of the notes produced.
展开▼
