FORM 2
THE PATENTS ACT 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(See Section 10; rule 13)


TITLE OF THE INVENTION Improved Speed Acquisition System for Vehicle-Pass by Noise Measurements
APPLICANTS
TATA MOTORS LIMITED, an Indian company
Having its registered office at Bombay House,
24 Homi Mody Street, Hutatma Chowk,
Mumbai 400 001 Maharashtra, India
INVENTORS
Mr. Amol Adinath Shewale and Dr. Mllind Narayan Ambardekar
of TATA MOTORS LIMITED an Indian company
having its registered office at Bombay House,
24 Homi Mody Street, Hutatma Chowk,
Mumbai 400 001 Maharashtra, India
PREAMBLE TO THE DESCRIPTION The following Complete specification particularly describes the invention.


FIELD OF INVENTION
This invention is related to an Improved Speed Acquisition System for Vehicle-Pass by Noise Measurements more particularly to a digital circuit to make Speed Sensor output compatible with a wireless system for Vehicle Pass-By Noise Measurements. This invention relates to a digital circuit using J-K flip-flop which is designed to convert 0-5 Volt pulse output of any type of Speed Sensor, RPM sensor, Tachometer with optical sensor in 0-5Volt square wave signal with 50% duty cycle. Application will be for the sensors used to record engine-speed using a wireless system during Pass by Noise Testing of a vehicle.
BACKGROUND OF THE INVENTION
There is a requirement of wireless transmission of an engine -speed signal in Vehicle Pass by Noise Test as per new Method B of Std. ISO 362-1:2007(E). The whole procedure using all instruments is well explained by Fig. 3. During this Test, it is required to record a Pass-by-noise-signal of a passenger car or a Test-vehicle (17) running on a smooth road (18) by Micro-phones (19) kept on Left Hand Side and Right Hand Side at a distance of 7.5 m from a central line as a function of the engine-revolutions per minute [RPM]. For this purpose, usually a wireless or Telemetry system is used.
For the engine-speed measurement, a Fiber Optic Sensor and Tachometer (20) are used with a Transmitter (21) and a Radio Antenna (22) placed on the vehicle. The Receiver (23) kept on the other side of the Track transfers the signal to a data acquisition system (24) with a Laptop (25) which also receives the real time-signals of the Micro-phones. A Radar (26) is used to sense longitudinal position of the vehicle. With all these input, the vehicle Pass-by noise can be synthesized as a function of the engine-RPM as well as the distance traveled by the vehicle between AA and BB lines
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sensed by a pair of Photo-cells (27) and Reflectors (28) kept at the beginning and end of the Test.
The Fiber Optic Sensor gives an electrical output compatible with the wireless system. Tachometer is used to display the engine- RPM to Driver. But the output of tachometer is pulse-output which is not compatible for wireless system.
The wireless system accepts only the 0 to 5 Volt square wave rpm signal with 50% duty cycle, i.e., its HIGH (5Volt) time and LOW (0 Volt) time of one cycle is equal. Though the fiber-optic sensor satisfies this requirement, it is used along with wireless system. The cost and time required for its set-up is higher and additional. Fiber optic sensor is said as additional requirement because tachometer with optical sensor is already fitted for engine RPM measurement to display the RPM to driver. But the tachometer output is 0 to 5 Volt pulses. This is not compatible with the wireless system. So there is a need to design an electronic circuit to match the output of tachometer wireless system.
THE OBJECTIVE OF THIS INVENTION
The main object of this invention is to obviate the above drawbacks.
Another object of this invention is to eliminate the requirement of Fiber Optic sensor. This will reduce the cost of Fiber Optic sensor, installation time of Fiber Optic sensor.
Yet another object of this invention is to make the Wireless system used during measurement compatible with all types of pulse output engine-speed sensors, tachometers for ease of operation of Inventory of Laboratory.
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SUMMARY OF THIS INVENTION
An Improved Speed Acquisition System for Vehicle-Pass by Noise Measurements comprising at least one rotating pulley with at least a reflecting sticker coupled with a tachometer to sense speed of said pulley, wherein output of the tachometer is transformed by a transforming digital circuit to transform signal to square wave and send it to a wireless transmitter to transfer the transformed signal to wireless receiver.
Out put of said wireless receiver goes to data acquisition and processing system for vehicle Pass by noise measurement.
The transforming digital circuit comprising at least one power supplying unit to give constant 5 Volt supply for circuit, digital edge triggered flips flop connected to input of a NPN Transistor through at least one resistor.
BRIEF DESCRIPTION
Fig. 1 shows a Circuit diagram of electronic circuit diagram of System for Vehicle-Pass by Noise Measurements according to instant invention.
Fig. 2 shows a J-K flip-flop according to instant invention.
Fig 3 shows an overall Pass by noise test setup of the vehicle running on the track.
Fig 4 shows block diagram of old and new setup
DETAILED DESCRIPTION
Referring now to the drawings wherein the showings are for the purpose of illustrating a preferred embodiment of the invention only, and not for the purpose of limiting the same.
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Now referring Fig. 1 shows a Circuit diagram of electronic circuit designed to make the pulse output of tachometer compatible for wireless system. It consists of power supply IC7805 (1) to give constant 5 Volt supply (7) for circuit, Digital edge triggered flips flop IC7476 (2). The output of tachometer is connected to CLOCK (8) pin of JK flip flop. The JK flip flop is used in a toggle mode, i.e. J (9) and K (10) are kept to logic HIGH level i.e. 5 Volt. So as per Fig. 2B Truth table, its output toggles between HIGH (5 Volt) and LOW (0 Volt) levels for every trigger clock pulse. Thus the two pulses of output of tachometer give square wave output at output pin Q (13) of JK flip flop. The output of JK flip flop is connected to the input of NPN Transistor (4) through resistor (3) R3 to avoid loading effect due load impedance. The resistor (3) R3 provides correct biasing conditions for the Transistor (4). The resistors (3) Rl and R4 are pull down and pull up resistors respectively. By using two or more even numbers of reflector sticker glued on rotating pulley, we will get the square wave signal with 50% duty cycle.
Fig. 2 shows a J-K flip-flop: A. Standard symbol; B. Truth Table; C. Timing diagram. 0 means Low level (0 Volt), 1 means High level (5 Volt), X means irrelevant state i.e. high or low level, J, means trailing edge of electrical signal i.e. 5 Volt to 0 Volt transition,
Fig 3 shows an overall Pass by noise test setup of the vehicle running on the track.
Fig 4 shows block diagram of old and new setup. It clearly shows that elimination of Fiber Optic sensor is achieved by introducing electronic circuit. Thus the cost and installation time of setup is drastically reduced.
A single-channel wireless system being specially developed to suit needs of an existing data acquisition system is expensive, which increases the cost of total set-up.
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But this wireless system has a limitation that it accepts only the 0-5V square wave rpm signal with 50% duty cycle, i.e., its HIGH time and LOW time is equal. Though only the fiber-optic sensor satisfies this requirement and not the existing tachometers or speed sensors.
Output signal level of the Fiber-optic sensor depends upon duration of reflected light incident on it. The requirement of 50% duty cycle signal is achieved by using a paper with the 50% black surface and 50% white surface.
At present setting up of the fiber optic sensor involves following steps:
• Take a print of half black and half white circle of diameter approx. equal to target rotating pulley
• Stick the paper on pulley
• Fit the fiber optic sensor such that its focus will be adjusted on the paper
• Start the engine and adjust a trigger level of the fiber-optic conditioning amplifier such that it gives the square wave output. As the paper has 50% black and white surface, the square wave output will be of 50% duty cycle.
Above steps are time-consuming as compared with following steps used in instant invention of setting up of Tachometer:
• Fit the optical sensor such that its focus will be adjusted on a rotating pulley.
• Stick the reflector tape on the pulley.
Also, tachometer needs to be installed irrespective of requirement of wireless system for display of engine RPM for Driver to drive the vehicle as per test conditions. Thus use of electronic circuit saves the setting up time and cost of Fiber Optic sensor. This will help in reducing overall time of vehicle pass-by noise testing comparatively at low cost.
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The J-K is a five-input device. The J and K inputs are for data. The CLK input is for the clock; and the PS and CLR inputs are the preset and clear inputs, respectively. The
outputs Q and are the normal, complementary outputs respectively.
With such a circuit, the output of the tachometer is compliant with the wireless system used during vehicle Pass-by-noise system. The concept was proved on a passenger car in a whole operating band of vehicle speeds on a Test-Track and it can be used on any type of vehicle.
The foregoing description is a specific embodiment of the present invention. It should be appreciated that this embodiment is described for purpose of illustration only, and that numerous alterations and modifications may be practiced by those skilled in the art without departing from the spirit and scope of the invention. It is intended that all such modifications and alterations be included insofar as they come within the scope of the invention as claimed or the equivalents thereof.

We claim
1. An Improved Speed Acquisition System for Vehicle-Pass by Noise Measurements
comprising:
- at least one rotating pulley with at least a reflecting sticker coupled with a
tachometer to sense speed of said pulley, wherein output of the tachometer is
transformed by a transforming digital circuit to transform signal to square wave and
send it to a wireless transmitter to transfer the transformed signal to wireless receiver.
2. The Improved Speed Acquisition System for Vehicle-Pass by Noise Measurements as claimed in claim 1, wherein out put of said wireless receiver goes to data acquisition and processing system for vehicle Pass by noise measurement.
3. The Improved Speed Acquisition System for Vehicle-Pass by Noise Measurements as claimed in claim 1, wherein said transforming digital circuit comprising:
- at least one power supplying unit to give constant 5 Volt supply for circuit, digital
edge triggered flips flop connected to input of a NPN Transistor through at least one
resistor.
4. The Improved Speed Acquisition System for Vehicle-Pass by Noise Measurements as claimed in claim 3, wherein said flip flop is a JK flip flop having a clock pin is connected to output of said tachometer.
5. The Improved Speed Acquisition System for Vehicle-Pass by Noise Measurements as claimed in claim 3, wherein said output is square wave output because of said flip flop is being employed in a toggle mode so that its output toggles between HIGH (5 Volt) and LOW (0 Volt) levels.
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6. The Improved Speed Acquisition System for Vehicle-Pass by Noise Measurements as claimed in claim 3, wherein said resistors are pull-down resistor Rl, pull-up resistor R4 and resistor R3 being provided to avoid loading effect due load impedance and correct biasing conditions for said NPN Transistor.
7. The Improved Speed Acquisition System for Vehicle-Pass by Noise Measurements substantially as hereinabove described with reference to the accompanying drawings.

Dated this 13th day of August 2009