IAA RAS Methods of transfer of ultrastable frequencies

IAA RAS Methods of transfer of ultra-stable frequencies to radio telescope А. Tsaruk, А. Vytnov, D. Ivanov Institute of Applied Astronomy of Russian Academy of Sciences 3 rd International VLBI Technology Workshop 10 - 13 November 2014 Groningen/Dwingeloo, the Netherlands

IAA RAS Overview Transfer methods of reference frequencies Components Unit forming the reference frequency Results 3 rd International VLBI Technology Workshop, 10 - 13 November 2014

IAA RAS Introduction Estimated frequency instability which must be provided for coherence losses less than 1% on 1 hour integration time IAA Transactions, 2006, V. 15, P. 140 -155 [Trudy IAA RAS(in russian)] 3 rd International VLBI Technology Workshop, 10 - 13 November 2014 3

IAA RAS Transfer methods of reference frequency 100 MHz to radio telescope • Transmission of the 100 MHz signal via RF cable with amplification. • Transmission of the 5 MHz signal via RF cable with amplification and multiplication. • Modulation of the optical signal by radio frequency 100 MHz and its transmission via fiber optic cable with demodulation on the radio telescope. 3 rd International VLBI Technology Workshop, 10 - 13 November 2014 4

IAA RAS Transfer methods of reference frequency 100 MHz to the radiotelescope 3 rd International VLBI Technology Workshop, 10 - 13 November 2014 5

IAA RAS Components LOW NOISE FREQUENCY MULTIPLIERS x 10 x 2 Ultra-Low Phase Noise: -143 d. Bc/Hz @ 1 Hz -170 d. Bc/Hz @ 1 k. Hz -176 d. Bc/Hz @ 100 k. Hz AMPLIFIERS DISTRIBUTION AMPLIFIER FIXED GAIN Low phase noise: -158 d. Bc/Hz @ 10 Hz -172 d. Bc/Hz @ 10 k. Hz 3 rd International VLBI Technology Workshop, 10 - 13 November 2014 6

IAA RAS Components Laser module Connector Type Wavelength Frequency Range FC/APC Optical receiver Connector Type FC/APC 1. 55 μm Wavelength 1. 31 -1. 55 μm 0. 1 -7000 MHz Frequency response irregularity ± 3 d. B Maximum optical -25 d. B attenuation Relative Intensity -140 d. B/Hz Noise Frequency Range 0. 1 -7000 МHz Return loss -25 d. B 3 rd International VLBI Technology Workshop, 10 - 13 November 2014 Optical isolator Connector Type FC/APC Insertion loss 0. 41 d. B Isolation 47. 5 d. B Optical circulator 7

IAA RAS Reference frequency transmission via fiber optic cable 3 rd International VLBI Technology Workshop, 10 - 13 November 2014 8

IAA RAS Cable delay compensation scheme 3 rd International VLBI Technology Workshop, 10 - 13 November 2014 9

IAA RAS Unit forming the reference frequency signal Ground part 3 rd International VLBI Technology Workshop, 10 - 13 November 2014 Antenna part 10

IAA RAS Unit forming the reference frequency signal (antenna part) Supply stabilization Ripple and noise < 3 m. V Temperature stabilization The internal temperature +35˚С at an external temperature of +5˚С. . . +40˚С 3 rd International VLBI Technology Workshop, 10 - 13 November 2014 11

IAA RAS Results 3 rd International VLBI Technology Workshop, 10 - 13 November 2014 12

IAA RAS Conclusion 1. The device is developed for the reference signal transmission to the radio telescope, allowing to transmit the signal of the reference frequency by optical and RF cable. 2. Introduced frequency instability in both methods of transfer reference frequency avoids the coherence loses greater than 1% on time interval of 1 hour. 3. At the moment there is an installation of the designed formation block of the reference frequency on the radio telescopes RT-13 produced by IAA RAS. Their future operation will show efficiency of the proposed methods for transmitting reference frequency on the radio telescope in real conditions. 3 rd International VLBI Technology Workshop, 10 - 13 November 2014 13

IAA RAS Thank you!