SU603373A1 - Blood flow meter - Google Patents

Description

one

This invention relates to medical technology, namely, hemodynamic recorders using radioactive indicators.

A device for measuring blood flow through a radioactive indicator is known, containing a series-connected sensor, a coincidence circuit controlled by a time relay (timer), a pulse counter and two registers, each of which has a code-analog converter loaded on a logarithm diode connected to the output the signal arrives at the indicator. To form control commands to rewrite the contents of the counter in the registers and reset them to the zero state, the timer output includes five triggers, each of which EET certain time quasistability conditions required for vsholneni corresponding command.

The drawback of the device is the low measurement accuracy due to the presence of analog elements, namely, logarithmic diodes and two code-analog converters. So, for example, a change in ambient temperature of 10 ° C causes a twofold change in the current of the logarithm diode.

The purpose of the invention is to improve measurement accuracy.

This is achieved by the fact that the device contains a delay circuit and a frequency divider, whose input is connected to the sensor, and the output is connected to the control input of the pulse counter and the time relay input, the output of the time relay is connected to the second code of the coincidence circuit and the trigger input whose output is connected to the input syn. register timing and through the delay circuit to the zero input of the pulse counter.

The drawing shows a block diagram of a device for measuring blood flow.

Claims (1)

The device for measuring the blood flow contains a series-connected sensor 1, circuit 2. The time signal controlled by the relay 3 signal, the impulse counter 4, the register C and the indicator 6. A frequency divider 7 connected to the sensor is connected to the counter control input of the counter 4 and the start input of the relay 3 time, the output of which through the trigger 8 / is connected to the forward dynamic synchronization input of the register 5 and; through the delay circuit 9 to the converting input of the counter 4 pulses. The device operates as follows. In the initial state 4. “(to) KO) frequency divider 7, trigger 8, counter 4 and register 5 are set to zero. In this case, there is no signal at the output of circuit 2. Pulses with an average frequency rt (H :) from sensor 1 continuously receive 7 frequencies from the coeffiin input divider divider N division. equal to approx; 1OOO. By the time H corresponding to the appearance at the output of the divider 7 of the first pulse, the number of pulses JH (t) di.J «oe-) t4 ° (l-e-«), arrives at its input. i: tMtJ - “f where It (i. is the average frequency of the pulses at time i, is equal to rt (t,) W (, - NL). The output pulse of the dividers 7 starts the time relay executed with a steady state 44: equal to, for example, 0.1 sec and simultaneously switches the counting direction of the counter 4 to addition. The sensor pulses with a frequency And (t) open at time scheme 2 coincident arrive at the counting input counter 4, which during this time registers the number of pulses H (i |) (ng-N The falling edge of the first control pulse and the time relay sets the trigger 8 to the single state. By the time the corresponding output of the divider 7 of the second pulse appears, the number of pulses enters: e r (i) di it a a W W-2N, where ll (ij) - the average frequency of the pulses at the moment of time 1 is equal, respectively: /, Ko-2Nfl. The second divider pulse starts the time relay and simultaneously switches the counting direction of the counter 4 to the subtraction. During the time di in C4 | ) 4i (5) At. As a result of the calculation, the number of (BUT-QW) A - |; - (Ho-2Na). which, after writing to register 5, lights up on the display of indicator 6. The contents of counter 4 in register 5 are recorded by a signal received at the dynamic synchronization input of register 5 from the inverse output of trigger 8, which returns to its initial state, at the falling edge of the second control pulse of the relay 3 times. After that, the signal from the CX8MA 9 output of the delay is fed to the input R, the counter 4, setting it to the zero state. The next measurement is similar. At the same time, indicator 6 shows the result of the previous measurement, which, taking into account the occupied / H-A-l "100 /, is equal to the measured parameter I, which characterizes the blood flow through the area of the organism under study. Thus, the device has a higher measurement accuracy, since the information is processed only in a discrete form and without a logarithm operation. Claims An apparatus for measuring blood flow, comprising a time relay, a trigger, a series connected sensor, a coincidence circuit, a pulse counter, a register, and an indicator that differs in that. that, in order to increase the measurement, it will hold a delay circuit and a frequency healer whose input is connected to the sensor, and the input is connected to the control input of the pulse counter and the input of the time relay, the input of the time relay is connected to the second input of the coincidence circuit and the trigger input, visa 11 of which is connected to the register synchronization input and through the delay circuit to the first pulse counter input. Sources of information taken into consideration in the examination: 1. French Patent No. 1458122, p. A 61 B, 1967.