RU1803978C - Quantum frequency standard - Google Patents

Abstract

Usage: quantum electronics, passive-type quantum frequency standards. SUMMARY OF THE INVENTION: The quantum frequency standard includes a controlled crystal oscillator 1, a phase-shifting circuit 2, a phase modulator 3, a frequency multiplier 4, a selective amplifier 5, a synchronous detector 6, an integrating circuit 7, a low-frequency oscillator 8, and a quantum discriminator 9. Inclusion in the auto-tuning circuit phase-shifting chain with a certain temperature coefficient of the phase leads to a decrease in the instability of the output frequency. 2 ill.

Description

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The invention relates to quantum electronics and can be used in passive high-precision quantum frequency standards (RNFs).

The aim of the invention is to reduce the instability of the output frequency.

In FIG. 1 presents a structural diagram of the RNF; in FIG. 2 is an example of a phase shifting chain.

KSCh (Fig. 1) contains a controlled crystal oscillator 1, a phase-shifting chain 2, a phase modulator 3, a frequency multiplier 4, a selective amplifier 5, a synchronous detector 6 and an integrating circuit 7, as well as a low-frequency generator 8, connected in series to an automatic frequency control ring and quantum discriminator 9.

The basis of the operation of the KSS is a comparison of the frequency of the controlled crystal oscillator 1 with the highly stable resonant frequency of the atomic transition of the quantum discriminator 9 using the AFC ring.

For operation of the AFC ring, phase modulation is introduced from the low-frequency generator 8, and a reference signal is supplied to the synchronous detector b through a different input to filter and synchronously detect the error signal at the output of the quantum discriminator 9.

In the case of detuning the carrier of the multiplied frequency of the controlled crystal oscillator 1 relative to the resonant frequency of the atomic transition of the quantum discriminator 9, an error signal is generated at the output of the latter with a frequency equal to the modulation frequency. The error signal is extracted by a selective amplifier 5, converted by a synchronous detector 6 to a constant voltage of positive or negative polarity, depending on the sign of the detuning, and filtered by an integrating circuit 7. The constant output voltage is supplied to the controlled crystal oscillator 1, compensating for the frequency detuning of this generator relative to the resonant frequency of the atomic transition of the quantum discriminator 9.

The phase-shifting chain 2 connected between the controlled crystal oscillator 1 and the phase modulator 3 has a phase temperature coefficient (Tf.ts.), opposite in sign to the phase temperature coefficient (Tp) of the phase modulator 4 of the frequency multiplier, and the absolute value approximately N times less, where N is the frequency conversion coefficient in frequency multiplier 4 and phase modulator 3. Due to this inclusion, the temperature coefficient of the phase of the output signal

frequency multiplier 4 is reduced. In this case, the conversion of ambient temperature fluctuations to frequency fluctuations of the carrier of the output signal of the frequency multiplier 4 is weakened, which leads to a decrease in the deadband of the AFC ring and, therefore, to a decrease in the frequency instability of the output signal of the entire RNF, since the frequency dispersion

the output signal in a first approximation is proportional to the variance of fluctuations in the ambient temperature and the temperature coefficient of the phase of the signal conversion circuit from the controlled

crystal oscillator 1 to quantum discriminator 9.

The absolute value of the temperature coefficient of the phase of the phase-shifting chain 2 satisfies the relation

ITy.H.I

0.5

1Tf.ts. | N

1,5

describing the range of possible values at which a positive effect is achieved. Above and below, the absolute value of Tf.ts. limited to a 50% change relative to the optimal value of Tu.h. / N. At the boundary

values Tf.ts. the overall temperature coefficient of the phase of the conversion circuit is reduced by 2 times compared with the known device, which corresponds to the frequency dispersion of the output signal of the RNF by 2 times and

a decrease in the instability of the frequency of the output signal of the RNF by about 1.4 times.

The phase shifting chain 2 is sequentially included in the AFC ring. Its delay should be minimal,

not more than a third of the constant time of the AFC ring to ensure ring stability, to limit the inertia of processing frequency perturbations of the controlled crystal oscillator 1,

In FIG. Figure 2 shows an example of a phase-shifting chain with a R2 thermistor as a temperature sensor.

Thus, in RNS at normal temperature, characterized by the value

temperature and the dispersion of its change, the dispersion of the frequency change is reduced by 2 or more times the output signal of the frequency multiplier 3 and, therefore, the frequency instability of the entire RNG is reduced

1.4 times or more compared to the known KSCh.

In addition, the RNG will have a reduced value of the frequency instability of the output signal when changing as

temperature dispersion as well as average ambient temperature. This leads to the expansion of the operating temperature range of the RNG, operational capabilities and a decrease in the temperature coefficient of the frequency.

Claims (1)

The claims A quantum frequency standard that contains a “phase modulator, frequency multiplier, quantum discriminator, selective amplifier, synchronous detector, an integrating circuit and a controlled quartz oscillator, as well as a low-frequency emitter, the output of which is connected to another rfiM inputs of the phase modulator and synchronization detector, characterized in that, in order to reduce the instability of the output frequency, a phase-shifting circuit with a temperature-dependent phase shift is introduced into it gom opposite sign temperature dependent phase shift in the phase modulator and a frequency multiplier, the value of which is selected from ratios of 0.5 | TkFpch1 1Tkfts1 -N 1,5 where Tkfpch and N are the temperature coefficient of the phase and the frequency conversion coefficient in the phase modulator and frequency multiplier; Tkfts - temperature coefficient phase shifting chain phases and the time constant of the phase-shifting circuit is less than a third of the constant time of the automatic frequency control ring, while the controlled quartz the generator is connected to the phase modulator through a phase-shifting chain. Figure 1