Electromagnetic Field Pickup for Musical Instruments

• US 20090223353A1
• Filed: 03/03/2009
• Published: 09/10/2009
• Est. Priority Date: 03/04/2008
• Status: Active Grant

• Current Assignee: Robert Francis Joseph Loftus
• Original Assignee: Robert Francis Joseph Loftus
• Inventors: Loftus, Robert Francis Joseph
• Granted Patent: US 8,129,607 B2
• Time in Patent Office: Days
• US Class Current: 84/726
• CPC Class Codes: G10H 2220/431 Use of microwaves
• CPC Class Codes: G10H 2220/565 Shielding, electromagnetic or magnetic, e.g. for transducers, i.e. for controlling, orienting or suppressing magnetic fields or for preventing unintentional generation, propagation and reception of electromagnetic energy in electrophonic musical instruments, their vicinity or their interconnections
• CPC Class Codes: G10H 3/18 using a string, e.g. electric guitar mechanical features G10D1/085

Abstract

An electromagnetic field pickup (10) for a musical instrument including an electromagnetic signal generator (12), an electromagnetic field transducer (18), a mixer (28), the electromagnetic signal generator (12), the electromagnetic field transducer (18) and the mixer (28) are respectively connected in series, the electromagnetic signal generator (12) is also connected directly to the mixer (28), so constructed and arranged that when power is supplied to the electromagnetic field pickup (10) an audio electrical signal of substantially same pitch, intonation and sustain as a vibrating element (22) of the instrument is generated.

Claims

1. An electromagnetic field pickup for a musical instrument comprising:

a) an electromagnetic signal generator;

b) an electromagnetic field transducer;

c) a mixer;

the electromagnetic signal generator, the electromagnetic field transducer and the mixer are respectively connected in series;

the electromagnetic signal generator is also connected directly to the mixer;

so constructed and arranged that when power is supplied to the electromagnetic field pickup an audio electrical signal of substantially same pitch, intonation and sustain as a sound vibration from a vibrating element of the musical instrument is generated.

2. The electromagnetic field pickup as recited in claim 1 further comprising a filter connected to the mixer.

3. The electromagnetic field pickup as recited in claim 2 further comprising an audio amplifier connected to the filter.

4. The electromagnetic field pickup as recited in claim 3 where the mixer is a mixer diode biased to operate in a linear region of the mixer diode'"'"'s range of operation.

5. The electromagnetic field pickup as recited in claim 4 where the electromagnetic field transducer includes an array of dielectric chip antennas.

6. The electromagnetic field pickup as recited in claim 5 in which the dielectric chip antennas are oriented with respect to the vibrating element so that a radiated field produced by the dielectric chip antennas has a same polarization as the vibrating element.

7. The electromagnetic field pickup as recited in claim 4 where the electromagnetic field transducer is a waveguide antenna having at least one slot.

8. The electromagnetic field pickup as recited in claim 7 where alignment of the waveguide antenna with respect to a string of the vibrating element is such as to place the slot substantially at right angle to the string and to place the string substantially over a centre of the slot so that a radiated field emitted from the slot has a same polarization as the string.

9. A method for generating a musical frequency audio electrical signal comprising a step of:

subtracting a first electromagnetic signal from a second electromagnetic signal to produce a difference signal;

the first electromagnetic signal and the second electromagnetic signal are of substantially same frequency;

the first electromagnetic signal is modulated by vibration of a vibrating element of a musical instrument to produce the second electromagnetic signal;

the difference signal is the musical frequency audio electrical signal of substantially same pitch, intonation and sustain as a sound vibration of the vibrating element of the musical instrument.

10. The method as recited in claim 9 further comprising steps of:

a) transmitting a first electromagnetic field towards the vibrating element;

b) receiving a second electromagnetic field from the vibrating element;

the first electromagnetic field is derived from the first electromagnetic signal;

the second electromagnetic field is derived by re-radiation and modulation of the first electromagnetic field;

the second electromagnetic signal is derived from the second electromagnetic field.

11. The method as recited in claim 10 further comprising a step of filtering out additional signals generated with the difference signal.

12. The method as recited in claim 11 where transmitting the first electromagnetic field includes transmitting a radio frequency field.

13. The method as recited in claim 11 where transmitting the first electromagnetic field includes transmitting a microwave frequency field.