Boots – shoes – and leggings
Patent
1980-04-17
1982-06-08
Smith, Jerry
Boots, shoes, and leggings
179 84VF, 307522, 328138, 364726, G01R 2302, G06F 15332
Patent
active
043342736
ABSTRACT:
An apparatus for detecting a tone signal in a telephone switching system is provided in which a calculation, in particular, multiplication is performed by a table look-up process in a digital memory, instead of using a conventional complicated multiplier. A tone signal of a particular frequency in a telephone line is detected through a discrete Fourier transform process (DFT), by the calculation of s(i)=x(iT).times.sin(i2.pi.fT), c(i)=x(iT).times.cos(i2.pi.fT), S=.SIGMA.s(i), C=.SIGMA.c(i), and P=S.sup.2 +C.sup.2. In the above calculation, the multiplication (x(iT).times.sin(i2.pi.fT), and x(iT).times.cos(i2.pi.fT)) is performed by a table look up method in a read only memory (ROM). Thus, the calculation is simplified. Further, the ROM has cells for only the discrete particular levels of multiplicands and/or the multipliers to reduce the capacity of the ROM, and the ROM is referred to by the multiplicand and/or the multiplier through the conversion of the same by a coefficient number generator.
REFERENCES:
patent: 3824471 (1974-07-01), Mills
patent: 4100378 (1978-07-01), Claasen et al.
patent: 4164036 (1979-08-01), Wax
I. Koval et al., "Digital MF Receiver Using Discrete Fourier Transform", IEEE Trans. on Communications, vol. COM-21, No. 12, 12-1973, pp. 1331-1335.
Kokusai Denshin Denwa Co. Ltd.
Smith Jerry
LandOfFree
Signal processing system using a digital technique does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Signal processing system using a digital technique, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Signal processing system using a digital technique will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-555736