SU599351A1 - Analogue-digital converter - Google Patents

Description

The invention relates to the measurement and conversion of electrical signals, to digital recording devices for analog signals on a foyer of random noise. Known analog-digital conversions. based developers. on integrating the desired signal and digitizing it with the help of the amplitude-time transducer l. However, they have low accuracy. Also known is an analog-to-digital converter containing a series-connected crystal oscillator, a control trigger, a frequency divider and a conversion cycle counter, a scan time switch connected to the frequency divider, an attenuator connected to the first input of the sampling device with an amplitude-simultaneous converter, and a strobe generator connected to the transform result register 2; Such analog-to-digital converters of the useful signal against the background of random noise have insufficient density due to the incomplete use of the sweep time of integration for the desired signal .. The purpose of the invention - improving conversion accuracy. This is achieved by the fact that a converter containing serially connected 1 var generator, a control trigger, a frequency divider and a conversion cycle counter, a sweep time switch connected to the frequency divider, an attenuator connected to the first input of the sampling device with an amplitude-time converter, a gated oscillator connected to the conversion result register further comprises a second sampler with an amplitude-time converter; the input of which is connected to the output of the attenuator, and the other input - to the output of the control trigger, a two-input OR circuit, inputs to which are connected to the outputs of amplitude-time converters, and a second frequency divider whose input is connected to the output of the struttable generator and the control input to the sweep time switch. The drawing is a functional electrical circuit of the device.

The analog-to-digital converter contains a crystal oscillator 1, the output of which is connected to the counting input of control trigger 2. The outputs of this trigger are connected to the second inputs of devices 3 and 4 of the sample, to the first inputs of which a convertible analog signal is fed through the input attenuator 5. The outputs of the devices 3 and 4 of the sample are connected to the inputs of the AMP-time converters (WUA) b and 7 push-pull integration. Thus, at the inputs of the first WUA b and the second WUA 7, the input signal is alternately present

The outputs of the WUA 6 and 7 are connected to the inputs of the OR circuit 8. The pulses from the output of the OR circuit 8. control the operation of the generator being shooted 9, at the output of which bursts of pulses are formed.

This pulse sequence through the controlled frequency divider 10 is fed to the input of the conversion result register 11.

The signal of the end of each conversion is removed from one of the outputs of the trigger 2 control and, through the control divider 12, the frequency arrives at the counter 13 measurement cycles. The digital code at the output of this counter simultaneously controls the sweep. The division factors of the control divider 10 and 12 frequencies are equal and are set by the sweep time switch 14.

in the case when the sampling duration is minimal and equal to the duration of one conversion cycle, the division factors of the controlled dividers 10 and 12 are set equal to one, and in the result register 11 the code corresponding to the number of pulses received on it is fixed. input during one conversion cycle,

At the same time, the number of measurement cycles at the meter 13 will receive a pulse after each conversion cycle of the input signal.

Increasing the sweep time by tn times compared to the minimum value is done by setting the division factor of the controlled dividers 10 and 12. For etrm, the duration of each sample due to the controlled divider 12 is increased by I1. those. during this sweep time, the amplitude-time converters B and 7 perform m conversion cycles. Moreover, their alternate connection to the input signal ensures its continuous averaging over the entire sampling time.

The number of pulses at the output of the gated oscillator 9 during the sampling time at this also increases in times as compared with their number during one conversion cycle. These pulses are fed to the input of a controlled frequency divider 10, the division factor of which is also equal to tn. Thus, the controlled divider 10 performs a statistical averaging of the conversion results tn, and on the measurement result register 11 the digital code is recorded corresponding to the average value of the input voltage over the sampling time. At the same time, the WUA conversion characteristic is the same as with the minimum sampling duration.

The presence of a counter 13 of the number of measurement cycles simultaneously controlling the sweep of the radio spectrometer, obs. It generates a synchronous conversion into a digital code of an input analog signal in accordance with its change under the action of a sweep of a radio spectrometer.

Claims (2)

1 .. Zelenin V.P. and others. 1024-channel storage of magnetic resonance signals, - Instruments and experimental technique, M., 1968. 2. Technical specification of the Varicnn radio spectrometer.