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A floating point analog-to-digital converter for use in a digital induction logging tool is disclosed. Floating point samples of phase quadrature components of the receiver signal are obtained. Each sample contains a digital word representing the exponent of a floating point number and digital word

A floating point analog-to-digital converter for use in a digital induction logging tool is disclosed. Floating point samples of phase quadrature components of the receiver signal are obtained. Each sample contains a digital word representing the exponent of a floating point number and digital word representing its magnitude. A voltage-to-frequency converter produces an output frequency proportional to the magnitude of the component signal. The resulting frequency signal is counted over a predetermined time inverval. At the completion of each time interval, the count is shifted until a predetermined magnitude is reached. The number of shift pulses required to reach this magnitude represents the exponent. The resulting shifted count represents its magnitude.

대표청구항 ▼

A floating point analog-to-digital convertor for converting an input analog signal into floating point digital signals, each digital signal having a digital code representative of the exponent of a floating point number and a digital code representative of its magnitude, the convertor comprising: (a

A floating point analog-to-digital convertor for converting an input analog signal into floating point digital signals, each digital signal having a digital code representative of the exponent of a floating point number and a digital code representative of its magnitude, the convertor comprising: (a) a voltage-to-frequency convertor for generating a digital clocking signal having a frequency proportional to the magnitude of the input analog signal; (b) a comparator for generating a count direction control signal according to the instantaneous polarity of the analog input signal; (c) an up-down counter responsive to the count direction control signal for counting up or counting down in response to clock pulses generating means of the digital clocking signal during a predetermined time period; (d) a shift register having a bit position for each bit of said up-down counter and responsive to shift pulses for storing and shifting at the end of each predetermined time period the count from said up/down counter one bit position for each shift pulse in a direction to obtain a predetermined magnitude for the count contained in a predetermined sub-set number of output bits of said shift register, the set of bits having a sign bit and a most significant bit (MSB), the sub-set of shift register output bits forming the magnitude of the floating point digital sample; and (e) a shift pulse counter for counting the number of shift pulses applied to said shift register, the count in said shift pulse counter forming the exponent of the floating point digital signal.