SU1370787A1 - Device for measuring dynamic parameters of d-a converters - Google Patents

Abstract

The invention relates to electrical measuring equipment and can be used to measure the dynamic parameters of digital-to-analog converters containing an internal register. The purpose of the invention is to expand the field of application by making it possible to measure the parameters of digital-analog converters with an internal register. The meter contains a pulse generator 1, registers 2 and 3, a frequency divider 4, a shift register 5, a switch 6, an adjustable voltage source 7, a reference voltage source 8, voltage dividers 9 and 10, a switch 11, pulse drivers 12 and 13, the adder 14, the amplifier-limiter 15, the oscilloscope 16, the inverter 17, the delay element 18, the element 19 And, the element 20 OR, the keys 21 and 22 and the meter 23 of the pulse duration. Introduction to the meter of two pulse formers 12 and 13, pulse meter 23, inverter 17, OR element 20 and delay element 18 allows measuring the time of setting up the digital-to-analog converter with an internal register, as well as the time for writing the code to the internal register of the digital-analog converter. 3 il. § (P 00 o 00

Description

The invention relates to electrical measuring equipment and can be used to measure the dynamic parameters of digital-to-analog converters containing an internal register.

The purpose of the invention is to expand the field of application by making it possible to measure the parameters of digital-analog converters with an internal register.

Figure 1 shows the functional diagram of the proposed meter; 2 and 3 are timing diagrams of signals on the code of the main nodes of the meter.

The dynamic parameter meter of D / A converters (Fig. 1) contains a generator of 1 pulses, registers 2 and 3, a divider 4 frequencies, a shift register 5, a switch 6, an adjustable voltage source 7, a reference voltage source 8, dividers 9 and 10 for example switch 11, formers 12 and 13 pulses, adder 14, limiting amplifier 15, oscilloscope 16, inverter 17, delay element 18, element 19, element OR 20, switch 21 and 22, and pulse width meter 23.

The meter works as follows.

Before measurement, code N is entered into register 2, and code Nj is entered into register 3, switch 6 is set to the upper position by supplying potential element O at the first input. code N goes through switch 11. Pulses from the output of pulse generator 1 (Fig. 2a and 3a) through delay element 18 (Fig. 2c) arrive at the input of the first pulse generator 12, which generates pulses (Fig. 2d), which are of a much longer duration records that are through the element t OR 20 (Fig. 2g) is fed to the input of the information recording resolution in the internal register of the measured DAC, the output of which generates a voltage proportional to the N code supplied to the second input of the adder 14. To the first input of the adder 14 from the outputs of the keys 21 and 22 alternately receive voltages + uV and - dU (FIG. Ze), which are formed from the output signals

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source 8 reference voltage with the help of dividers 9 and 10 voltage. The signal from the output of the adder 14 through the limiting amplifier 15 is fed to the information input of the oscilloscope, to the synchronization input of which the delayed and inverted signal of the generator 1 arrives. As a result, three lines are observed on the oscilloscope screen corresponding to the signal from the output of the measured DAC and from the output of dividers 9 and 10 voltages Adjusting the signal at the output of the regulated voltage source 7 (which goes to the third input of the adder 14) compensates the output signal of the measured DAC, with the result that on the oscilloscope screen the compensated signal from the DAC output lies midway between the levels + AV and -AV .

To measure the time of setting the signal at the output of the measured DAC when the code N. changes to N. The switch 6 is set to the lower position by applying And 19 level 1 to the first input. The element 19 is opened and the pulses from the generator 1 code are sent to the control input of the switch 11 (a multiplexer can be used as a switch), which is used to change the code at the information input of the measured DAC (Fig.26). The pulses from the output of the generator 1 are fed to the delay element 18, the delay time of which is longer than the switching time of the switch 11. The signal from the output of the delay elements is fed to the input of the first driver 12 pulses, and through the inverter 17 (fig.2d) to the input of the second driver 13 pulses which is made with adjustable pulse duration. When measuring the time of setting the signal at the output of the measured DAC, the pulse duration at the output of the second generator of 13 pulses is set to be obviously longer than the recording time in the internal register of the measured DAC.

Impulse from the output of the first shaper 12 through the element 20 (Fig.Zh) is written in the internal register of the measured DAC code N. As a result, at the output of the DAC is formed

voltage proportional to code N (Figure 2h). The shaper 13 generates a write pulse (Fig. 2e), which, through the OR element 20 (Fig. 2g), enters the write enable input of the internal register of the measured DAC, a code change occurs and a controlled transient process of establishing the signal at the output of the measured CAG1 begins (fig.2z). At this moment, the next sweep of the oscilloscope 16 is started again. When a pulse appears on the second and then on the third outputs of the shift register 5 (fig. 3d) the element And 19 is closed, the output signal of the measured DAC corresponds to the transient mode, to the third input adder 14 through the keys 21 and 22 are connected alternately levels + AV and -AV. Synchronization of the oscilloscope with delayed and inverted pulses of the oscillator 1 makes it possible to observe simultaneously a controlled transient at the output of the measured DAC and setting boundary zones. The settling time is determined by means of an oscilloscope by determining the moment of the last entry of the transient process into the zone bounded by the levels + dU. The process of measuring the time of setting the output signal of the measured DSL ends there.

To measure the recording time in the internal register of the measured DAC, the pulse duration at the output of the second pulse shaper 13 is gradually reduced (Figure 2e) entering the write enable input to the internal DAC register after changing the code from NJ to N. At the output of the switch 11. If the recording pulse duration is less than the recording time in the internal DAC register, then not N code is written to the register, but some error code N. The value of the signal at the output of the measured DAC at the error code N is fixed (taking into account and from the output of the regulated voltage source 7) does not fall into the establishment zone equal to tijV. The minimum pulse duration at the output of the second driver 13, at which the code N. is written to the internal register of the measured DAC, and the compensated signal at the DAC output falls into the mouth zone

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is equal to the measured write time in the internal register of the measured DAC. The measurement of the time of recording information in the internal DAC register is carried out using a pulse width meter 23.

Thus, an advantage of the invention is the possibility of measuring the time of setting the output signal of the measured DAC and the time of writing the code in the internal DAC register.

Claims (1)

Invention Formula A dynamic parameter meter for digital-to-analog converters containing a switch, the first and second inputs of which are input buses, respectively, of a logical zero and a logical unit, and the output through an AND element is connected to the control input of a switch, the first and second information inputs of which are connected to the corresponding outputs of the first and second the registers, the switch outputs are the output information bus, a pulse generator, the output of which is connected to the second input of the element I and h Through a frequency divider - with a clock input of the shift register, the first output of which is connected to the third input of the AND element, and the second and third outputs are connected to the control inputs of the first and second keys, respectively, the outputs of which are combined and connected to the first input of the adder, the second input of which is the input information bus, the third input is connected to the output of the adjustable voltage source, and the output through the amplifier-limiter is connected to the information input of the oscilloscope, the information inputs of the first and second to The switches, respectively, through the first and second voltage dividers are connected respectively to the first and second outputs of the reference voltage source, the first output of which is an output bus .1, which is different in that, in order to expand the field of application by making it possible to measure the parameters of digital-to-analog converters with an internal register, a pulse width meter, two pulse formers, an OR element, an inverter, and a delay element whose input is connected to the output g are entered into it pulse generator, and the output is connected to the inputs of the first pulse shaper and inverter, the output of which is connected to the synchronization input of the oscilloscope and through the second pulse shaper - to the input of the pulse width meter and the first input of the OR element, the second input of which is connected to the output of the first pulse shaper, and the output is an output trigger bus. FIG. 2 P  I П П П П ППППППП J Фцг.З