Ultrasonic bloodstream diagnostic apparatus with dual displays of

Abstract

A ultrasonic bloodstream diagnostic apparatus wherein the frequencies of Doppler shift ultrasound information are analyzed by a frequency analyzer to derive a power spectrum represented by N-bit data. The N-bit data comprises (K+M+L) bits, where K represents the number of binary 0's in the highest order bit positions and varies in the range between zero and N-M, M represents a fixed number of significant bits immediately following the binary 0's and L represents the number of insignificant bits in the lowest order bit positions immediately following the M significant bits, where K+L equals N-M. A data compression technique is employed to conver the N-bit data to (m+l)-bit data by a data conversion circuit, with the m bits respectively identical to the M bits and l bits being a binary representation of the number of the L bits. A microprocessor derives a signal representing the average frequency of the power spectrum from the (m+l)-bit output data signal. The (m+l)-bit output data signal is converted by a conversion memory to a form suitable for display by an algorithm which reconverts it to N-bits and logarithmically compresses the latter.