초록 ▼

The speed of an object is measured using a device which includes a transmitter spaced a predetermined distance from a receiver. A first sound wave is propagated through air with a first velocity, typically zero velocity. A second sound wave is propagated through air, the air having a second velocity

The speed of an object is measured using a device which includes a transmitter spaced a predetermined distance from a receiver. A first sound wave is propagated through air with a first velocity, typically zero velocity. A second sound wave is propagated through air, the air having a second velocity which approximately equals the air speed of the object. The difference in time between the two sound waves reaching the receiver is measured and used to calculate the air speed of the object, which is then displayed to the user. The device is readily mounted on a pair of glasses wherein the user can read the displayed air speed without involving the user's hands.

대표청구항 ▼

[ I claim:] [1.] An apparatus for measuring the air speed of an object, said apparatus comprising:a tube adapted to allow air to flow through;a transmitter mounted in said tube;a receiver mounted in said tube a predetermined distance from said transmitter, said receiver adapted to receive sound wave

[ I claim:] [1.] An apparatus for measuring the air speed of an object, said apparatus comprising:a tube adapted to allow air to flow through;a transmitter mounted in said tube;a receiver mounted in said tube a predetermined distance from said transmitter, said receiver adapted to receive sound waves transmitted from said transmitter;an amplifier having an input lead coupled to an output lead of said receiver, said amplifier adapted to amplify a first signal generated by said receiver from said sound waves;a flip flop pair having a first input lead coupled to an output lead of said amplifier, said flip flop pair adapted to detect wave transitions of said first signal;an oscillator having an input lead coupled to an output lead of said flip flop pair, said oscillator generating a second signal at an output lead of said oscillator when said flip flop pair asserts an on-signal at said flip flop pair output lead;a counter having an input lead coupled to said oscillator output lead, said counter being coupled to said transmitter and said flip flop pair, said counter adapted to count cycles of said second signal;a controller coupled to said counter, said controller having a first output lead coupled to a second input lead of said flip flop pair, wherein said controller asserts a set-signal on said controller first output lead thereby causing said flip flop pair to assert said on-signal thereby causing said oscillator to generate said second signal, said counter counting cycles of said second signal, and wherein said controller de-asserts said set-signal a predetermined amount of time after said controller asserts said set-signal, thereafter said flip flop pair de-asserts said on-signal upon detecting the next wave transition of said first signal thereby causing said oscillator to stop generating said second signal, said counter stopping with a cycle count indicative of said air speed, said controller adapted to receive said cycle count from said counter;a display having an input lead coupled to a second output lead of said controller, said display for displaying said air speed; anda zero switch having an output lead coupled to a first input lead of said controller.