US 8,914,242 B2 · Signal processing in guided wave cutoff spectroscopy

Abstract

The present invention includes a guided microwave spectroscopy system (1) that eliminates the need for an automatic gain control feature by providing multiple signal processing paths having differing fixed voltage gains. An emitted signal which exits a test chamber (2) containing a material under test is simultaneously amplified by at least a first fixed gain amplifier (4) and a second fixed gain amplifier (7). The output signal of each amplifier is separately digitized and then normalized for further digital signal processing by a computer (13) in order to determine parameters of the material under test which may have variable microwave radiation characteristics that are a function of the frequency of the signal emitted into the test chamber. During the signal processing step a system clock (121) causes the computer to sample only an integral number of complete output signal cycles. A calibration protocol (136-154) is conducted based on laboratory samples of each potential material to be processed by the system (1).

Claims20

Dependent claims

A system for processing a signal received while operating a guided microwave spectroscopy device, comprising:

(a) a variable frequency signal source;
(b) a test chamber, the test chamber containing a material under test;
(c) a received signal path, the received signal path containing radio frequency energy initially generated by the variable frequency signal source after the radio frequency energy has been altered by passing through the material under test;
(d) a plurality of received signal amplifiers, each received signal amplifier being interconnected to the received signal path, each received signal amplifiers producing an output signal, and;
(e) a computer, the computer being interconnected to the plurality of received signal paths, the computer being programmed to determine parameters of the material under test in response to the output signal produced by each of the plurality of received signal amplifiers.

2 more elements

A guided microwave spectroscopy signal processing device, comprising:

(a) a variable frequency oscillator adapted to radiate electromagnetic energy through an object;
(b) a receiver, the receiver being adapted to intercept at least a portion of the electromagnetic energy after the electromagnetic energy has passed through the object, the receiver further comprising:
(i) a first signal processing path having a first amplification factor;
(ii) a second signal processing path having a second amplification factor;
(c) a computer, the computer independently sampling and independently processing the first signal processing path and the second signal processing path in order to determine at least one property of the object;
and
(d) a system clock, the system clock synchronizing the computer such that substantially all signal samples recorded by the computer during a sampling period contain a substantially whole number of complete signal waveform cycles.

4 more elements

Dependencies are inferred from the claim text.

Signal processing in guided wave cutoff spectroscopy

Life of this patent

Signal processing in guided wave cutoff spectroscopy

Life of this patent

Abstract

Claims20