JPS63168155A - Doppler signal regeneration method and recording/regeneration apparatus - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for reproducing a door alarm signal of an ultrasonic door alarm diagnostic apparatus and a recording/reproducing apparatus, which are mainly used as medical equipment. More specifically, the method reproduces baseband (audio) Doppler signal pairs recorded in the recording means in different directions,
Re-analyzing using an analysis circuit including a complex FFT performer and a linear combiner, reproducing method for observing the results, and recording baseband (audio) Doppler signal pairs for each direction in recording means and reproducing them. Then, reanalyze it using the analysis circuit and record/playback when observing! Regarding location.

(Prior art) Ultrasonic Doppler diagnostic equipment emits CW (3m continuous wave) or pulse-modulated ultrasound into the body, measures the Doppler shift of the echo signal, and detects moving bodies in the body (such as blood flow). The target) velocity, flow m, etc. are used as subsides.

FIG. 2 is a block diagram showing a receiving section of a conventional CW Doppler device using an analog calculation method. In FIG. 2, the echo signal is amplified by receiving amplifier 1 and then
It is divided into channels and detected by a quadrature detection circuit. That is, the signal pair is multiplied by two reference waves having a phase difference of 90 degrees from each other from the carrier oscillator 2 in a multiplier 3, and then unnecessary high frequency components and low frequency components are removed by a band pass filter 4. The Doppler signal pair obtained at this stage is generally referred to as i (in-phase) and q (quadrature) baseband Doppler signals. This signal pair is passed through a Hilbert transformer (wideband 90 degree phase shifter) 5 which outputs the two input signals with a 90 degree phase difference.
Directional separation is performed by a linear coupler 6 which outputs the addition and subtraction results of the two input signals. In other words, U is the door alarm signal of the target approaching in the line of sight direction.
It is separated into SB (upper sideband) and SS (lower sideband), which is the door signal of the target moving away.

Thereafter, the USB and LSB signals are analyzed in each direction by a frequency analyzer 7 such as a Tunagraph, and the results are displayed on a display device 8.

FIG. 3 is a block diagram showing a receiving section of a CW Doppler device using a digital calculation method. Note that each symbol in FIG. 3 has the same meaning as in FIG. 2. In FIG. 3, the pair of Doppler signals i and q output from the bandpass filter 4 is input to an analysis circuit 9 consisting of a complex FFT calculator and a linear combiner. Here, frequency analysis and linear combination are performed, and outputs for each direction of USB and LSB are provided to the display device 8 and displayed. Since such a digital calculation method provides more accurate analysis results than the analog method described above, it is currently used in place of the analog method described above.

By the way, in such a Doara receiver, a two-channel recording means, ie, a stereo tape recorder, etc. is generally used as a recording means for the Doara signal. If a pair of base panto door signals of 1 and q are recorded on each channel of this recording means, a problem arises in left and right phase matching due to the pinch roller contact, one-sided stretching of the tape, etc. during playback.

Therefore, the i and q base panto door signal pairs are usually converted into USB and LSB by a Hilbert transformer and a linear combiner.
It is converted into a pair of Doppler signals in the form of and recorded on a stereo tape recorder.

(Problems to be Solved by the Invention) Generally, hardware and software for FFT calculations are required to operate at very high speed. For this purpose, a Doppler signal pair in the form of USB and LSB reproduced from a stereo tape recorder is input to an analysis circuit comprising a conventional FFT arithmetic unit configured to input the i and q baseband Doppler signal pairs. Adding functions such as processing, signal analysis, and display results in a lot of waste and reduced performance in hardware and software.

The present invention enables USB data recorded in a stereo tape recorder to be used without causing such waste or deterioration of performance.
and LSB format Doppler signal pair, and the signal can be analyzed by an analysis circuit consisting of a conventional i and q signal input type complex FFT calculation device and a linear combiner, The purpose is to provide a playback device.

(Means for Solving the Problems) In order to achieve the above object, the Doppler signal reproducing method and recording/reproducing apparatus of the present invention have the following configuration.

That is, in the first invention, a Doppler signal pair of i (in-phase) and q (quadrature) obtained by orthogonal detection of an ultrasound echo signal from a subject is recorded in the form of a USB signal and an LSB signal by an external recording means. Regenerate the recorded signal and perform addition and subtraction operations on the two signals corresponding to the USB signal and the LS[3 signal. After creating a pair of Doppler signals in the form of i and q, they are input to an analysis circuit consisting of a complex FFT (fast Fourier transformation! k) operator and a linear combiner to perform frequency analysis and linear combination. (upper sideband) signal and LSB (lower sideband)
The configuration is such that the signal and direction are separated and displayed.

The second invention is such that during recording, the output from the quadrature detection circuit that inputs the ultrasonic echo signal from the subject and converts it into a pair of i and q Doppler signals is 90 degrees with respect to the two input signals. Hilbert transformer that outputs with a phase difference of
The USB signal and LSB signal created by the linear combiner that outputs the addition and subtraction results for two input signals are input to the recording means, and during playback, the USB signal and the LSB signal from the recording means are input to the recording means. The LSB signal is guided through a path of a linear combiner and a Hilbert transformer, and the i and q signal pair created is connected to a complex FFT calculator and a linear combiner, and the Doppler signal pair is converted into a USB (upper sideband ) signal and LSB
(lower sideband) signal and a switching means for inputting the signal to an analysis circuit that outputs it as a signal.

(Example) Hereinafter, the present invention will be explained in detail with reference to the drawings.

FIG. 1 is a block diagram showing a receiving section of a CW Doppler apparatus for implementing the present invention. In addition, in Figure 1,
Components having the same functions as those in FIG. 3 are denoted by the same symbols as in FIG. 3, so their explanations will be omitted here.

In the circuit configuration shown in FIG. 1, reference numeral 10 is an external two-channel stereo tape recorder that records and reproduces a pair of Doppler signals in the form of USB and LSB.

11 is a signal exchange board (signal switch), and the white and black circles at the intersections of the vertical and horizontal lines are switches between these two lines. In normal use, measurements are taken and analyzed on one hand, while Doppler signals are recorded on the other.
The black circle switch turns on. On the other hand, when reproducing and analyzing the Doppler signal pair recorded in the form of USB and LSB and displaying it on the display device 8, only the white circle switch is turned on.

In the above configuration, during normal use, the Doppler signal pair of i and q, which is the output of the bandpass filter 4, is
One input is input to the signal exchange board 11, and one is input to the analysis circuit 9 including an FFT demultiplexer and a linear combiner through the switch point of the black circle, where frequency analysis and linear combination are performed.
Outputs for each direction of the SB are obtained and displayed on the display device 8. Then, the other signal is again input to the Hilbert converter 5 via the black circle switch point, and its output is input to the signal exchange board 11 again, and then input to the -order coupler 6, and the US
The signal is separated into B and LSB Doppler signal pairs. - The output of the secondary combiner 6 is given to the stereo tape recorder 10 via the signal exchange board 11, and the USB and L
SB Doppler signal pairs are recorded.

Next, the operation when reproducing the recorded Doppler signal pair and analyzing and displaying it will be explained. In this case, turn off the switch marked with a black circle on the signal exchange board 11 and turn on the switch marked with a white circle. The output of the stereo tape recorder 10 (LIS 8 and LSB signals) is input to the signal exchange board 11, and input to each -order combination 6 via the switch points indicated by white circles.

This output is inputted again to the signal exchange board 11, and then inputted to the Hilbert transformer 5, where it undergoes Hilbert inverse transformation and is converted into a Doppler signal pair of i and q.

This signal pair is inputted via the signal exchange board 11 to an analysis circuit 9 consisting of a complex FFT arithmetic unit and a linear combiner, and the output for each direction is displayed on the display device 8 in the same manner as described above.

As explained above, switching between the two modes of recording and playback analysis display is performed by the signal exchange board, and during recording, the i and q base panto door signal pairs are converted into USB and LSB format by the Hilbert converter and linear coupler. When recorded, this signal is converted into a Doara signal pair in the form of i and q using a linear combination circuit and a Hilbert transformer. A predetermined analysis and display can be performed by inputting this into an analysis circuit including a linear coupler.

Note that the present invention is not limited to the above embodiments, and various modifications can be made within the scope of the claims. For example, it may be used in a receiving section of a pulsed ultrasound Doppler device.

(Effects of the Invention) As described above, according to the method for reproducing door alarm signals and the recording/reproducing apparatus of the present invention, the following effects can be obtained.

In other words, just by adding a few circuits, the recorded USB
Since the signal pair can be regenerated in the form of
A lot of waste and capacity loss in hardware and software can be avoided.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a receiving section of a CW Doppler device using a digital operation method according to an embodiment of the present invention, and FIG. 2 is a block diagram showing a receiving section of a CW Doppler device using a conventional analog calculation method. , FIG. 3 is a block diagram showing a receiving section of a conventional CW Doppler device using a digital calculation method. 1...Reception amplifier, 2...Carrier oscillator, 3...
- Multiplier, 4...Band pass filter, 5...Hilbert transformer, 6...-order combiner, 7...Frequency analyzer, 8...Display device, 9...Analysis circuit , 10...
- Stereo tape recorder, 11... signal exchange board.

Claims (2)

[Claims] (1) Analysis of i (in-phase) and q (quadrature) Doppler signal pairs obtained by orthogonal detection of ultrasound echo signals from the subject using a complex FFT (fast Fourier transform) calculator and a linear combiner. The circuit performs frequency analysis and linear combination, and the US
In a Doppler signal processing method in which a B (upper sideband) signal and an LSB (lower sideband) signal are directionally separated and displayed, the Doppler signal pair is recorded in advance in the form of a USB signal and an LSB signal by a recording means. and play the corresponding USB signal and LSB
The two results obtained by adding and subtracting two signals corresponding to the signals are given a phase difference of 90 degrees, i
A method for reproducing a Doppler signal, which comprises creating a pair of Doppler signals in the form of and q, and then inputting the pair to the analysis circuit. (2) Input the ultrasound echo signal from the subject and i(
It has a quadrature detection circuit that outputs a pair of Doppler signals (in-phase) and q (quadrature), a complex FFT calculator, and a linear coupler, and outputs the pair of Doppler signals as a USB (upper sideband) signal and an LSB (lower sideband) signal. In a Doppler signal processing device equipped with an analysis circuit that converts and outputs a signal, and a display device that inputs the signal from the circuit and displays it based on the USB signal and the LSB signal, a Hilbert transformer that outputs with a phase difference of degrees, a linear combiner that outputs the addition and subtraction results of two input signals, and a recording means that records and reproduces the USB signal and the LSB signal; At the time of recording, the signal pair i and q from the quadrature detection circuit is guided through the path of the Hilbert transformer and the linear coupler, and the created USB signal and LSB signal are input to the recording means, and at the time of playback, the signal pair of i and q is input to the recording means. A Doppler comprising switching means for guiding the USB signal and LSB signal from the means through a path of a linear coupler and a Hilbert transformer, and inputting the created i and q signal pair to the analysis circuit. Signal recording/
playback device.