| 摘要 |
<p>PURPOSE:To eliminate noise or to insert a synchronizing signal without missing of information by multiplying a specific window function to an input voice signal at an optional time interval, extracting the result, applying Fourier transformation, dividing and modifying optionally the transformed signal, providing a space and processing and outputting the signal with the converted step. CONSTITUTION:An input voice signal is converted into a data in 1 word 12-bit sequentially by an AD converter 2, enters a shift register SR3, is latched by an SR4 and fed to a multiplier 5. On the other hand, a hamming window coefficient is fed one by one word to other input terminal of the multiplier 5, and the result of multiplication is fed to an FFT (Fast Fourier Transform) transforming device 6. The transforming device 6 applies Fourier analysis (FFT) for a short time and generates a complex data. The multiplier 7 multiplies a prescribed coefficient to the said data so as to a short time Fourier spectrum. A spectrum modification circuit 8 is stored with the said signal at each prescribed frequency band, an erroneous address is moved optionally and the band is split and modified so that the space is provided to a band of noise/synchronizing signal. Moreover, the signal is outputted via the processing corresponding to the said processing by an inverse FFT10.</p> |
