SU1693713A1 - Digital phase discriminator - Google Patents

Description

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(21) 4732561/09

(22) 08/25/89

(46) 11/23/91. Bul №43

(72) V.G.Aristov and B.G.Ivanov

(53) 621.376 (088.8) (56) Theoretical foundations of radar. / Ed. Dulevich.- M .: Soviet radio, 1978, p. 352.

(54) DIGITAL PHASE DISCRIMINATOR

(57) The invention relates to a measurement technique and can be used for

measuring the phase difference of two segates. The purpose of the invention is to increase the stability of the transmission coefficient while simplifying the device. The digital phase discriminator with inputs 2, 7 contains phase shifter 1, frequency divider 3 with n-bit input 5, counter 4, register 6. Simplifying the device eliminates the use of elements that introduce instability into the transmission coefficient of the digital phase discriminator. 2 yl

The invention relates to a measurement technique and can be used to measure the phase difference of two signals.

The purpose of the invention is to increase the stability of the transmission coefficient while simplifying the device.

Figure 1 shows the structural electrical circuit of a digital phase discriminator; 2 shows timing charts and a discriminatory characteristic.

The digital phase discriminator contains a phase shifter 1, the first input 2, a divider 3 frequencies, a counter 4, an n-bit input 5 divider 3 frequencies, a register 6, a second input 7.

The discriminator works as follows

The pulses from the first input 2, coming through the phase shifter 1 and the divider 3 frequency to the input C of the write code in counter 4, set the return code at the output of the last one, twice as small as the return code fed to the n-input input 5 (division factor Cd) counting input 1 of counter 4 pulses from the first input 2 are received directly. By the moment of arrival of the pulse from the second input 7 to the input C of recording the code in register 6, counter 4 will pass the number of pulses N, proportional to the interval between the pulses at the input C 4 and the pulse at the second input 7. In register 6, the code of the number AN N will be written / 2. If N CD / 2, then from the output of register 6 will be the reverse code of the phase difference. In the most significant, sign degrade of register 6, in this case it will be logical 1 If N Zhd / 2, then the output of register 6 will be the direct code of the phase difference. In the sign decimal register 6 in this case will be a logical O.

The number AN is proportional to the phase difference, and the discriminator has a sawtooth

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characteristic, the advantage of which is the maximum size of its linear segment. When the code at the discriminator output is zero, the signal at input C of counter 4 is half a period ahead of the signal at the second input 7, which ensures accurate operation of the discriminator due to the absence of the status of the input pulse edges in the most critical part of the characteristic and allows for the sign of the phase difference.

Phaser 1 per l :, for example, an inverter, if the input signal is a meander, also ensures accurate operation of the discriminator due to the lack of state of the pulse fronts at the inputs of the counter 4.

With a fixed code of the division factor of the frequency divider 3 Ko, the transmission coefficient of the discriminator is Ko / 3600.

Increasing the division ratio code of the Frequency Divider 3 reduces the frequency of the signal at input C of counter 4 and increases the transmission coefficient of the discriminator Co / 3600, which ensures the constancy of the overall transmission coefficient of the circuit divider - phase discriminator: (1 / Ko) - (Ko / 360 ° ) 1/360 ° when using the device in active frequency synthesis systems, when the divider 3 frequency is the system frequency divider.

If the signal-to-noise ratio deteriorates at the second input 7 in one oscillation period at the input C of counter 4, there may be more than one pulse relative to the second input 7. The zero offset of the characteristic 2 of the digital phase discriminator will not occur, since the device processes all pulses from the mixture at the second entrance 7. 7

Compared with the prototype, the proposed device is simpler and has better transmission coefficient stability due to the absence of a generator of counting pulses,

Claims (1)

a trigger for the formation of a temporary gate, an And element, two delay lines included in the prototype. The instabilities introduced by these blocks are absent in the device’s considered digital phase discriminator. At the same time, the advantages of the prototype are preserved in it; stable operation in synchronization mode, the formation of the sign of the phase difference, a wide range of reference frequencies, allowing the use of a discriminator in active frequency synthesis systems with a divider in the feedback circuit. The invention is a digital phase discriminator containing series-connected a phase shifter, whose input is the first input of the device, and a frequency divider, as well as a serially connected counter, the n-bit input of which is the input of the initial setup code phase difference, and a register whose output is a device output, characterized in that, in order to increase the stability of the transmission coefficient while simplifying the device, the enable input the register record is connected to the second input of the device, the phase shifter input and the output of the frequency divider are connected to the counting input and the write enable input of the counter, respectively, the n-bit input of the frequency divider is connected to the n-bit input of the dividing ratio code, and the bit inputs of the counter with 1 on (n-1) - y is connected to the bits of the input of the frequency divider, starting from the 2nd to the n-th bit, respectively, and the n-th bit of the n-bit input of the counter is connected to the logical 1 bus. Login C