Production of non-frequency proportional vibrato

• US 3,920,905 A
• Filed: 02/11/1974
• Issued: 11/18/1975
• Est. Priority Date: 02/11/1974
• Status: Expired due to Term

• Current Assignee: Marmon Company
• Original Assignee: Paul H. Sharp
• Inventors: Sharp, Paul H.
• Primary Examiner(s): Cooper, William C.
• Assistant Examiner(s): Kemeny, E. S.
• Application Number:
  US05/441,031
• Time in Patent Office: 645 Days
• Field of Search: 179/1J 84/1.25
• US Class Current: 381/62
• CPC Class Codes: G10H 1/045 by electromechanical means

Abstract

Non-frequency proportional vibrato and like effects are achieved by cooperation of a device such as a modulated analog shift register that by itself produces frequency proportional modulation and other components which dynamically shift the frequency or phase of the processed signal. In one embodiment, the input signal is offset downward in frequency by - Delta f, processed by a modulated bucket brigade device, and subsequently shifted back in frequency by an amount + Delta f. In another embodiment, the signal is passed serially through a dynamic phase shifter and a modulated bucket brigade delay line. By driving the phase shifter and the delay line synchronously, the separately introduced modulation effects may be partially cancelled. The output signal from each embodiment exhibits vibrato or like modulation having non-frequency proportional percentage frequency deviation characteristics.

Claims

1. In apparatus for electronic superposition of vibrato upon electrical impulses having a spectrum extending throughout a substantial frequency range:

a. means forming an electrical input and and electrical output for said apparatus;

b. a first modulator for superimposing vibrato upon said electrical impulses with a depth of swing or frequency deviation substantially proportional to the frequency of the impulses;

c. a second modulator for superimposing vibrato upon said electrical impulses with a substantially constant frequency deviation;

d. means serially connecting said modulators between said electrical input and electrical output; and

e. common means for controlling said vibrato modulators in synchronism at a selected vibrato rate whereby the frequency swing of the superimposed vibrato of said modulators is algebraically additive controllably to change the characteristics of the vibrato spectrum from a linear frequency relationship.

2. The apparatus as set forth in claim 1 in which said modulators are connected in opposition whereby frequency shift is proportionately more greatly reduced at the lower spectrum.

3. The apparatus as set forth in claim 1 in which said first modulator is an analog shift register having a clocking means and in which said second modulator includes an impedance element that is dynamically changed, said common means being a low frequency oscillator in control both of said clocking means and said dynamically changed impedance.

4. The apparatus as set forth in claim 1 in which said first modulator is an analog shift register having a clocking means and in which said second modulator comprises a series of networks each including an impedance element dynamically changed, said common means being a low frequency oscillator in control both of said clocking means and all of the dynamically changed impedances of said networks.

5. In apparatus for electronic superposition of vibrato upon electrical impulses having a spectral range extending throughout a substantial frequency range:

a. a modulator for superimposing vibrato upon said electrical impulses with a depth of swing or frequency deviation substantially proportional to the frequency of the impulses;

b. a first device for superimposing a substantially constant frequency shift upon said electrical impulses;

c. a second device for superimposing a substantially constant frequency shift upon said electrical impulses;

d. the frequency deviations imposed by said devices being substantially equal and opposite; and

, e. means serially connecting the devices and modulator with the modulator interposed between the devices whereby the characteristics of the vibrato is not a direct linear function of frequency.