| 摘要 |
Physical characteristics of a material through which acoustic energy has been conducted and partly absorbed are inferred from the missing parts of the received spectrum. The signal 11, 20 is applied to an inverse filter arrangement 10, acting as a low-, high- or pass-band filter, connected to a white noise level generator 41 and the missing spectral content of the transmitted signal is built-up band-by-band. The arrangement comprises an amplifier 32, ADC 33, micro-processor 34. RAM 35. keyboard 40 and display means 36-39. The material under investigation may be an earth formation. <IMAGE> |
