Αποτελέσματα Αναζήτησης
The Theremin has two very high frequency oscillators (around 350 kHz). One of them is fixed, and the other is varied by the capacitance of your hand: it's the difference between the two frequencies which decides the pitch.
29 Δεκ 2004 · The theremin is played by carefully moving your hands near 2 antennas, one for volume and one for pitch. But how does it work? If you mix the signals of 2 rf oscillators, you will get many output signals. The most important signals are the sum and difference of both frequencies.
The theremin's sound is produced by the electronic principle of 'heterodyning' - when the frequency of the 'pitch' oscillator is subtracted from the frequency of a fixed oscillator, the resultant frequency produced falls within the range of human hearing, and this is what we hear through a speaker as sound.
27 Ιουν 2024 · The complete JFET-based theremin circuit includes a second oscillator, a mixer, and a circuit for the volume antenna. The second oscillator is stabilized at 470 kHz by a ceramic resonator, and so it must be possible to set the adjustable oscillator to this frequency.
Calibrating the Frequency Signal The frequency range for the Theremin should be at least two octaves (220 to 880 Hz). A second LabVIEW subVI called Scale Frequency.vi, as shown in Fig. 5, converts the second photometer signal level into a frequency level. The photometer input (0 to 6 V) is converted into an audio
Depending on your hand position and the adjustment of the instrument, the beat frequency can be anywhere from around 65 Hz to about 3 kHz (260 kHz minus 257 kHz). These are audio frequencies, and they correspond to a range that spans from about two octaves below middle C to about three-and-a-half octaves above middle C.
The oscilloscope can be connected between C2 and the input to 1C as shown in the image below. The output should be a square wave with a frequency of between 60-75 kHz. The frequency can be set by RV1 during tuning.
