Method and apparatus for remote measurement of vibration and properties of objects

An apparatus for remotely measuring properties of an object comprising:

• a signal generator for generating an electromagnetic signal;
• an amplitude modulator for amplitude modulating the electromagnetic signal with a modulating signal to produce an amplitude modulated signal;
• a transmitter for transmitting the amplitude modulated signal at an object;
• means for vibrating the object to modulate the amplitude modulated signal transmitted at the object;
• a first receiver for receiving a reflected amplitude modulated signal from the object;
• a second vibration receiver mounted with the first receiver for compensation for unwanted background or coupled vibration;
• a demodulator for demodulating the reflected amplitude modulated signal using the modulating signal to produce a demodulated signal;
• and
• a signal processor for extracting and analyzing a vibration waveform from the demodulated signal.

A method of remotely measuring vibration comprising:

• generating an electromagnetic signal;
• amplitude modulating the electromagnetic signal with an amplitude modulating signal to produce an amplitude modulated signal;
• transmitting the amplitude modulated signal at a vibrating object using a first transmitter;
• receiving a reflected amplitude modulated signal from the vibrating object using a first receiver;
• demodulating the reflected amplitude modulated signal using the amplitude modulating signal to produce a demodulated signal;
• compensating for vibration errors by determining displacements of the transmitter and receiver;
• and
• analyzing the demodulated signal.

A method for remotely determining properties of an object comprising:

• amplitude modulating an electromagnetic signal with an amplitude modulating signal to produce an amplitude modulated signal;
• transmitting the amplitude modulated signal at an object;
• vibrating the object;
• receiving reflected amplitude modulated signals from the vibrating object using a first receiver;
• compensating for unwanted vibration using a second receiver mounted with the first receiver;
• and
• processing the reflected amplitude modulated signals to extract information about the properties of the object.

A method of remotely measuring vibration, comprising:

• providing a non-coherent beam of light;
• amplitude modulating the non-coherent beam of light with an amplitude modulating signal to produce an amplitude modulated beam of light;
• transmitting the amplitude modulated beam of light at a vibrating object;
• object using a transmitter;
• receiving a reflected amplitude modulated beam of light from the vibrating object using a receiver;
• compensating for vibration errors by determining displacements of the transmitter and the receiver;
• and
• demodulating the reflected amplitude modulated beam of light using the amplitude modulating signal to extract vibration information from the amplitude modulated signal.

A microwave vibrometer, comprising:

• a signal generator for generating a first microwave frequency signal;
• a power splitter for splitting the first microwave signal into a reference signal and a signal to be transmitted;
• a circulator for transmitting the signal to be transmitted at a vibrating object, for receiving a phase modulated reflected signal from the vibrating object, and for decoupling the transmitted signal from the reflected signal;
• a first mixer for mixing the phase modulated reflected signal with an intermediate frequency signal to produce a first mixed signal;
• a second mixer for mixing the reference signal with the intermediate frequency signal to produce a second mixed signal;
• an I & Q demodulator for mixing the first mixed signal and the second mixed signal to produce a demodulated signal;
• and
• means for extracting and analyzing a vibration waveform from the demodulated signal.