IP Library Granted Patent US 7,230,418
Granted Patent B2
US 7,230,418 · App. 10/892,370 · Granted Jun 12, 2007

Flutter reduction apparatus and method

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Quick Facts
Patent No.
US 7,230,418
App. No.
10/892,370
Granted
Jun 12, 2007
Kind
B2
Abstract

A tachometer circuit includes a flutter reduction circuit and a tachometer. The tachometer circuit cancels pointer flutter in the tachometer without adversely affecting pointer response.

Claims (29)

1. A tachometer circuit comprising:

a tachometer; and

a flutter reduction circuit electrically coupled to and driving said tachometer, said flutter reduction circuit generating a voltage to cancel ripple voltages;

wherein said flutter reduction circuit including a high pass filter circuit; and a tachometer driver circuit electrically coupled to said high pass filter circuit, said high pass filter circuit filtering the unwanted input voltages and generating the voltage to cancel ripple voltages; and

said high pass filter circuit further includes an operational amplifier, said operational amplifier is biased by a bias signal from said driver circuit; and a voltage divider electrically coupled to said operational amplifier.

2. The tachometer circuit of claim 1 , wherein said voltage divider further comprises two resistors in connected series.

3. The tachometer circuit of claim 1 , wherein said operational amplifier outputs the voltage that is used to cancel rippled voltages.

4. The tachometer circuit of claim 1 , wherein the tachometer is an aircore tachometer.

5. The tachometer circuit of claim 1 , wherein said tachometer is an aircore mini-meter.

6. The tachometer circuit of claim 1 , wherein the tachometer is a motorcycle tachometer.

7. The tachometer circuit of claim 1 , wherein said high pass filter is connected to a charge pump filter capacitor.

8. The tachometer circuit of claim 1 , wherein a divider ratio for the voltage divider is approximately 10/47.

9. The tachometer circuit of claim 1 , further including input circuitry connected to said tachometer driver circuit.

10. The tachometer circuit of claim 1 , further including a one shot circuit connected to said tachometer driver circuit.

11. A flutter reduction circuit for use with a tachometer, said flutter reduction circuit comprising:

a high pass filter circuit; and

a driver circuit electrically coupled to said high pass filter circuit, said high pass filter circuit passing unwanted input signals to a first circuit within the driver adapted to cancel out the signals and said high pass filter circuit generating a voltage to cancel ripple voltages; and

wherein said high pass filter circuit further comprises:

an operational amplifier; and

a voltage divider electrically coupled to said operational amplifier.

12. The tachometer circuit of claim 11 , further including a one shot circuit connected to said driver circuit.

13. The flutter reduction circuit of claim 11 , wherein said voltage divider further comprises two resistors in connected series.

14. The flutter reduction circuit of claim 11 , wherein said operational amplifier outputs the voltage that is used to cancel rippled voltages.

15. The flutter reduction circuit of claim 11 , wherein said operational amplifier is biased by a bias signal from said driver integrated circuit.

16. The flutter reduction circuit of claim 11 , wherein the flutter reduction circuit connects to an aircore tachometer.

17. The flutter reduction circuit of claim 11 , wherein the flutter reduction circuit connects to an aircore mini-meter.

18. The flutter reduction circuit of claim 11 , wherein the flutter reduction circuit connects to a motorcycle tachometer.

19. The tachometer circuit of claim 11 , wherein said high pass filter is connected to a charge pump filter capacitor.

20. The flutter reduction circuit of claim 11 , further including input circuitry connected to said driver circuit.

Assignments (7)
RELEASE OF SECURITY INTEREST Recorded Dec 10, 2025
From: BMO BANK N.A.
To: AUTO METER PRODUCTS, INC.; AMEI HOLDINGS, INC.; COBB TUNING PRODUCTS, LLC
Reel/Frame 073177/0424 →
RELEASE OF SECURITY INTEREST Recorded Jan 19, 2023
From: COLE TAYLOR BANK
To: AUTO METER PRODUCTS, INC
Reel/Frame 062418/0637 →
SECURITY INTEREST Recorded Jul 30, 2014
From: AUTO METER PRODUCTS, INC.
To: BANK OF MONTREAL
Reel/Frame 033449/0556 →
RELEASE OF SECURITY INTEREST Recorded Sep 11, 2013
From: ANTARES CAPITAL CORPORATION
To: AUTO METER PRODUCTS, INC.
Reel/Frame 031186/0797 →
SECURITY AGREEMENT Recorded Jun 13, 2013
From: AUTO METER PRODUCTS, INC.
To: COLE TAYLOR BANK
Reel/Frame 030602/0942 →
SECURITY AGREEMENT Recorded Jul 28, 2006
From: AUTO METER PRODUCTS, INC.
To: ANTARES CAPITAL CORPORATION, AS AGENT
Reel/Frame 018015/0284 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Jul 16, 2004
From: SCHUBERT, THOMAS A.
To: AUTO METER PRODUCTS, INC.
Reel/Frame 015585/0010 →