Music – Accessories – Tuning devices
Reexamination Certificate
1999-03-01
2001-09-18
Fletcher, Marlon T. (Department: 2837)
Music
Accessories
Tuning devices
C084S455000, C084S47700R, C084SDIG001
Reexamination Certificate
active
06291755
ABSTRACT:
FIELD
The present invention relates to a digital electronic tuner for stringed musical instruments, particularly designed to be implanted into the sound box of the musical instrument with a digital display positionable to face a user.
BACKGROUND
Electronic tuners for stringed musical instruments use some kind of pickup head to sense the sound vibrations corresponding to the note being played and convert that vibration to an electrical signal. Some tuners use microphones to pick up the tone from air-transmitted sound but such detection is susceptible to error or difficulty in tuning due to ambient noise also picked up by the microphone. The operation of such circuits involves first amplifying and filtering the signal, and then detecting it in a microprocessor to determine the fundamental frequency of the tone being detected utilizing a suitable tuning algorithm. In some circuits this frequency is compared with the true fundamental frequencies of the notes which are stored in processor memory. The frequency of the closest note to the detected frequency of the tone being detected is determined after which various outputs may be provided. Some outputs use a series of flashing lights in the form of light emitting diodes to indicate the closest note. U.S. Pat. No. 5,388,496 issued to Miller et al. discloses an additional output which indicates whether the frequency of the detected tone is above or below the frequency of the closest note. Other kinds of displays such as a null meter, an oscilloscope screen, or coloured lights have been used. U.S. Pat. Nos. 4,312,044 issued to Baba and 4,434,697 issued to Roses discloses use of a multi-digit segment display and an alphanumeric display, respectively.
The location of the electronic and display of known guitar tuners ranges from units which are contained in separate boxes as in U.S. Pat. No. 3,901,120 issued to Youngquist to a display in the form of a series of flashing lights on the side of the guitar finger board as in Miller et al., supra. In Miller et al. the light display is connected by a cable to a casing mounted within the sound box of a guitar. For such an arrangement as in Miller, it would be necessary for a user to memorize which lights correspond to which notes as well as which colours indicate an out-of-tune tone being higher than the frequency of the note being played and which colours indicate an out-of-tune tone being lower than the frequency being played. It would also be necessary in Miller, supra., to connect the external cable from the casing within the sound box to the light display when it is desired to use the tuner.
Accordingly, it is an object of the invention to provide an improved tuner for a stringed musical instrument. It is a further object of the invention to provide a tuner for stringed musical instruments having an improved display. It is yet a further object to provide a tuner for stringed musical instruments implanted into the box and positionable so that it faces a user during tuning.
SUMMARY OF THE INVENTION
According to the invention there is provided a tuner for stringed musical instruments which has a transducer for converting sound vibrations of the strings to electrical signals and a body, either hollow or solid, with a front and back surface and a side surface extending between the front and back surface. The tuner has a tuner circuit mountable in an interior of said body, with an input of the tuner circuit having an input couplable to an output of said transducer. An output of the tuner circuit is connected to a digital display positioned or positionable so that it is visible to a player when the instrument is in a playing position. A first portion of the digital display is operative to automatically represent alphabetically, without reference to a corresponding mark or position, a reference note closest in frequency to a measured tone for all notes capable of being played on said stringed musical instrument. A second portion of the digital display is operative to represent a graphically intuitive indication of whether the measured tone has the same frequency as the reference note, whether the frequency of the measured tone is one of above and below the reference note, and a relative frequency difference between said measured tone and the reference note.
Preferably, the digital display is a multi-segment display and the graphically intuitive indication includes an top segment in the top half of the second portion of the multi-segment display, which top segment has an arrow pointing towards a top of the display and flashes at a rate proportional to a difference between the measured tone and the reference note when the measured tone is one of lower and -higher in frequency than the reference note and a lower segment in the bottom half of the second portion of the multi-segment display having an arrow pointing to a bottom portion of the digital display. The bottom segment flashes at a rate proportional to the difference between the measured tone and the reference note when the measured tone is another of lower and higher in frequency than the reference note. A median segment is located in the middle of the second portion of the multi-segment display, and is perpendicularly oriented relative to the top and bottom segments and lights when the measured tone is equal in frequency to the reference note.
The digital display may be mounted within, and substantially flush to, the side surface on a side closest to a player, the digital display facing the player when the instrument is in a playing position.
The tuner circuit may include a filter and AC decoupler operative to filter signals from the transducer to produce a filtered signal. An inverter and follower circuit may be operative to invert the filtered signal. A one shot circuit may be coupled to an output of the inverter and follower circuit and be triggerable in response to a second half of said filtered signal and be operative to produce a square wave output in response to being triggered. A processor may be coupled to the square wave output signal. The processor may be operative to detect a fundamental frequency of the square wave signal and compare it to reference frequency values corresponding to notes of a musical scale, determine a reference note having a frequency closest to the fundamental frequency of the square wave signal, digitally determine a relative difference between the fundamental frequency of the square wave signal and the reference note and output digital output signals to operate the digital display, including a first signal operative to carry information to alpha-numerically display the reference note and a second signal operative to carry information to graphically display the relative difference between the fundamental frequency of the square wave signal and the reference note.
The fundamental frequency of the square wave signal is determined by measuring the period of each of the square wave signal and then averaging the periods so determined to provide an average period. This average period is then used in examining a look up table in the processor non-volatile memory to select a frequency value therein corresponding to a frequency of a closest note to the note being played for display on the digital display.
The audio output may be coupled to an output of the record and playback apparatus and be operative to provide an audio output for the tuner circuit.
The audio output may include an amplifier coupled to an output of the digital record and playback apparatus, and a jack coupled to an external headphone.
A controls signal circuit may be coupled to the processor, a memory may be coupled to the tuner circuit output and be operative to store notes being played by a stringed instrument and detected by the tuner circuit, a single/timed input switch may be coupled to the controls signal circuit and be operative, in one position, to cause recorded notes stored in the memory to be displayed on the digital display one at a time in sequence with the order in which they were recorded and, in a timed position, to cause the entire
Burdett Carl
Collings Timothy
Hine Arthur H.
Richardson Brian
Fletcher Marlon T.
Hall Priddy Myers & Vande Sande
Hine Arthur H.
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