RU2691588C1 - Analogue-to-digital and digital-to-analogue conversion method with non-uniform amplitude quantisation - Google Patents

Abstract

FIELD: computer equipment.SUBSTANCE: invention relates to computer engineering. Method of analogue-to-digital and digital-to-analogue conversion with non-uniform amplitude quantisation consists in that before analogue-to-digital conversion input analogue signal is supplied to comparator with level of comparison equal to 1/10 of maximum value of ADC amplitude. If the input signal exceeds the comparison level, then the high-order ADC is assigned the value "1", if the input signal is less than the comparison level, the high-order bit is "0", the high-order bit is the control for the demultiplexer.EFFECT: technical result consists in expansion of dynamic range of radio systems in analog-to-digital and digital-to-analogue conversion of signals with equal capacity of ADC and DAC.1 cl, 2 dwg

Description

The invention relates to electronic computing and electronics, intended for analog-digital and digital-analog conversion and can be used in radar systems, navigation and communication, as well as in audio.

The closest technical solution (prototype) to the proposed is a method of expanding the dynamic range of the equipment, which consists in introducing N blocks of operational amplifiers with different gain factors, as well as a set of K1.N keys that connect their own amplifier. When transmitting / recording a signal in RAM, they are connected in such a way as to reduce the dynamic range of the recorded (or transmitted) signal. When processing (or receiving) a signal, the dynamic range expander also has N blocks of operational amplifiers that are connected using K2.N keys and restores the original signal by connecting the corresponding amplifier blocks [1] ..

However, the known method of expanding the dynamic range does not allow to fully realize its advantages, since it uses uniform quantization over the amplitude of the analog signal.

Achievable technical result - the expansion of the dynamic range of radio systems with analog-digital and digital-analog conversion of signals at the same bit ADC and DAC.

The technical result is achieved due to the fact that the proposed method and devices of analog-digital and digital-analog conversion with non-uniform quantization in amplitude, characterized in that before analog-digital conversion, the input analog signal is fed to the comparator with a level of comparing equal to 1/10 of the maximum value of the amplitude of the ADC; while if the input signal exceeds the level of comparing, then the most significant digit of the ADC is set to “1”, if the input signal is less than the level of comparing, the most significant bit will be equal to “0”; The analog-to-digital converter contains additional blocks: a comparator, two voltage sources, a demultiplexer; the input analog signal simultaneously arrives at the inputs of the comparator and the ADC with uniform amplitude quantization; if the input signal exceeds the level of comparing, the most significant bit is “1”, if it does not exceed, then the most significant bit is “0”; the high-order bit is the control for the demultiplexer, which determines which reference voltage source is connected to the uniform-quantization ADC modulo 2; the values of the reference voltages differ by a factor of 10; therefore, the quantization of the level for the high-order bit is performed modulo 10, and for the remaining N-1 bits, it is modulo 2; the digital-to-analog converter also contains additional blocks: a demultiplexer and two reference voltage sources, the values of which also differ 10 times; while the high-order bit arrives at the control input of the demultiplexer: if its value is “1”, then the first reference voltage source is connected to the DAC, if the high-power bit is “0”, then the second voltage source is connected to the DAC; the remaining N-1 bits come to the corresponding information inputs of the D / A converter and further digital-to-analog conversion is performed with uniform quantization modulo 2.

The method of analog-digital and digital-analog conversion with uneven quantization by level consists in that before analog-digital conversion the input analog signal is fed to a comparator with a level of comparing equal to 1/10 of the maximum value of the amplitude of the ADC. If the input signal exceeds the level of comparing, then the high-order ADC is set to “1”; if the input signal is less than the level of comparing, then the high-order bit is “0” (the high-order bit is the control for the demultiplexer).

The analog-digital converter contains additional blocks: a comparator, two sources of reference voltage (ION), a demultiplexer (Fig. 1). The input analog signal simultaneously arrives at the inputs of the comparator and the A / D converter with uniform amplitude quantization. If the input signal exceeds the level of comparing, equal to 1/10 of the maximum amplitude value, then the high-order bit takes the value “1”, if it does not exceed, then the high-order bit takes the value “0”. The leading bit is the control, if it is equal to "1", then the first reference voltage source is connected to the ADC with uniform amplitude quantization; if the high-order bit is “0”, then the second reference voltage source. The values of the reference voltages differ by a factor of 10, therefore quantization of the level in the most significant bit is done modulo 10. Analog-digital conversion for the remaining N-1 bits is done in the usual way with uniform quantization modulo 2 (N is the ADC bit width).

A digital-to-analog converter with non-uniform quantization in amplitude also contains additional blocks: a demultiplexer and two sources of reference voltage, the values of which also differ 10 times (Fig. 2). With digital-to-analog conversion, the high-order bit arrives at the control input of the demultiplexer; while if its value is “1”, then the first reference voltage source having a nominal value is connected to the DAC; if the high-order bit is “0”, then the second reference voltage source is connected to the DAC, which has a value of 1/10 of the nominal level. The remaining N-1 bits are fed to the corresponding information inputs of the D / A converter and the digital-to-analog conversion is performed with uniform quantization modulo 2.

We make a comparative estimate of the dynamic range for analog-to-digital conversion with a uniform and non-uniform method of quantization in amplitude with the ADC bit width - 16 bits.

For uniform quantization modulo 2 dynamic range

A = 6.02 × N = 6.02 × 16 = 96.32 dB.

So the values of the reference voltages differ 10 times, then in power this ratio will be 10 dB and in amplitude - 20 dB according to the formula:

For the proposed method of non-uniform quantization, the number of bits modulo 2 is 15 bits. modulo 10 - 1 bit.

A = 6.02 × (N-1) + 20 = 6.02 × 15 + 20 = 90.3 +20 = 110.3 dB.

Thus, the gain in dynamic range will be approximately 14 dB, which is extremely important for analog-digital conversion of weak signals.

Literature

1. RF patent № 2614345. IPC H03B 1/00. A way to expand the dynamic range in radio systems / Ryabov IV, Klyuzhev E.S., Dedov AN, Garifullina A.V. Appl. 21.12.2015. Publ. 03/24/2017. Bul № 9. - 7 p. (prototype).

Claims (1)

Analog-to-digital and digital-to-analog conversion with non-uniform quantization in amplitude, characterized in that before analog-to-digital conversion, the input analog signal is fed to a comparator with a level of comparing equal to 1/10 of the maximum amplitude of the ADC; while if the input signal exceeds the level of comparing, then the most significant digit of the ADC is set to “1”, if the input signal is less than the level of comparing, the most significant bit will be equal to “0”; The analog-to-digital converter contains additional blocks: a comparator, two voltage sources, a demultiplexer; the input analog signal simultaneously arrives at the inputs of the comparator and the ADC with uniform amplitude quantization; if the input signal exceeds the level of comparing, the most significant bit is “1”, if it does not exceed, then the most significant bit is “0”; the high-order bit is the control for the demultiplexer, which determines which source of the reference voltage is connected to the ADC of uniform quantization modulo 2; the values of the reference voltages differ by a factor of 10; therefore, the quantization of the level for the high-order bit is performed modulo 10, and for the remaining N-1 bits, it is modulo 2; the digital-to-analog converter also contains additional blocks: a demultiplexer and two reference voltage sources, the values of which also differ 10 times; while the high-order bit arrives at the control input of the demultiplexer: if its value is “1”, then the first reference voltage source is connected to the DAC, if the high-power bit is “0”, then the second voltage source is connected to the DAC; the remaining N-1 bits come to the corresponding information inputs of the D / A converter and further digital-to-analog conversion is performed with uniform quantization modulo 2.

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