Signal conversion device
First Claim
1. A signal conversion circuit for converting a periodic, analog, electrical input signal into an output signal differing from the input signal in amplitude and/or frequency and/or phase comprising:
- scaling means for changing the amplitude of the input signal so that the peak thereof equals a preselected value;
A/D converter means operatively connected to said scaling means for sampling the amplitude of the input signal and changing the sampled values to an equivalent set of digital words, each digital word corresponding to the value of its associated sample;
a comparison, subtraction and scale adjustment (CSSA) means operatively connected to said A/D converter means and to said scaling means for receiving the output of said A/D converter means and storing it until the next output thereof is received, and for comparing each present output sample (tn) of said A/D converter means with its prior output sample (tn-1) once each cycle of the input signal Vi of said signal conversion circuit, the present and prior output samples being used to correct the scaling of said scaling means;
ROM means operatively connected to said CSSA means so as to receive the output of said A/D converter means, in the form of output digital words, for storing at each digital word address thereof another digital word in accordance with pre-programmed values corresponding to the values of a desired output signal; and
D/A converter means operatively connected to said ROM means for converting the output digital words thereof into corresponding analog values.
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Abstract
A solid-state, signal conversion circuit for converting electrical, periodic analog signals to other analog signals of different amplitude and/or frequency and/or phase is disclosed. The input signal is demodulated, scaled and sampled and each sample converted, via an analog-to-digital (A/D) converter, to a digital word corresponding to the sample'"'"'s amplitude. The digital words address a ROM which has other words stored at the addresses in correspondence with the desired values for a preselected output signal. Scaling means is used to keep the input signal to the A/D converter at a constant peak value regardless of fluctuations in the signal level. A comparator and subtractor are used to invert the downslope of input signals to avoid ambiguity problems when the output signal frequency is an even multiple of the input signal frequency.
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Citations
4 Claims
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1. A signal conversion circuit for converting a periodic, analog, electrical input signal into an output signal differing from the input signal in amplitude and/or frequency and/or phase comprising:
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scaling means for changing the amplitude of the input signal so that the peak thereof equals a preselected value; A/D converter means operatively connected to said scaling means for sampling the amplitude of the input signal and changing the sampled values to an equivalent set of digital words, each digital word corresponding to the value of its associated sample; a comparison, subtraction and scale adjustment (CSSA) means operatively connected to said A/D converter means and to said scaling means for receiving the output of said A/D converter means and storing it until the next output thereof is received, and for comparing each present output sample (tn) of said A/D converter means with its prior output sample (tn-1) once each cycle of the input signal Vi of said signal conversion circuit, the present and prior output samples being used to correct the scaling of said scaling means; ROM means operatively connected to said CSSA means so as to receive the output of said A/D converter means, in the form of output digital words, for storing at each digital word address thereof another digital word in accordance with pre-programmed values corresponding to the values of a desired output signal; and D/A converter means operatively connected to said ROM means for converting the output digital words thereof into corresponding analog values. - View Dependent Claims (2, 3, 4)
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Specification