Low-Noise Hybrid Frequency Synthesizers Based on Direct Digital and Direct Analog Synthesis

2020 ◽  
Vol 63 (4) ◽  
pp. 308-313
Author(s):  
V. V. Romashov ◽  
K. A. Yakimenko ◽  
A. N. Doktorov ◽  
L. V. Romashova
Keyword(s):  
Frequency Synthesizers ◽  
Low Noise ◽  
Analog Synthesis ◽  
Hybrid Frequency

Low-noise hybrid frequency synthesizers based on direct digital and direct analog synthesis

2020 ◽  
pp. 51-56
Author(s):  
Vladimir V. Romashov ◽  
Kirill A. Yakimenko ◽  
Andrey N. Doktorov ◽  
Lubov V. Romashova
Keyword(s):  
Phase Noise ◽  
Frequency Synthesizers ◽  
Low Noise ◽  
Synthesis Methods ◽  
Noise Power ◽  
Frequency Synthesis ◽  
Noise Characteristics ◽  
Analog Synthesis ◽  
Hybrid Frequency ◽  
Offset Frequency

The research of the possibility of using hybrid frequency synthesizers based on direct digital and direct analog methods of frequency synthesis as heterodynes of modern spectrum analyzers constructed according to the superheterodyne scheme is presented. The main advantages of such synthesizers over traditionally used heterodyne schemes based on direct digital and indirect frequency synthesis methods are shown. The requirements for the heterodynes of the first mixing stages of spectrum analyzers are presented. A block diagram of a wideband heterodyne generating a frequency range from 4000 MHz to 8000 MHz with a step not exceeding 1 Hz is proposed. Formulas for calculating the main frequency ratios in the structure of the heterodyne have been developed. A mathematical model of phase noise power spectral density (PSD) depending on the offset frequency from the carrier is developed. The noise characteristics of the proposed scheme are studied using the model. It is determined that at the output frequency of the heterodyne equal to 4521,4 MHz, the level of phase noise PSD is: minus 90 dBc/Hz at the offset frequency equal to 100 Hz; minus 140 dBc/Hz at the offset frequency equal to 100 kHz. It is shown that the hybrid synthesizer based on direct digital and direct analog synthesis methods has an advantage in the level of phase noise from 5 to 30 dB over the low-noise heterodynes of modern spectrum analyzers at frequencies above 1 kHz from the carrier. Additional advantages of the proposed scheme are a simple architecture, low power consumption and high frequency tuning speed due to the absence of phaselocked loops in the structure of the heterodyne.

scholarly journals Low-noise hybrid frequency synthesizers for 5G technology

2019 ◽  
Vol 1399 ◽  
pp. 022025
Author(s):  
V V Romashov ◽  
K A Yakimenko ◽  
A N Doktorov
Keyword(s):  
Frequency Synthesizers ◽  
Low Noise ◽  
Hybrid Frequency

scholarly journals Analysis of Noise Characteristics of Multichannel Systems of the Formation of Signals of Georadars with Synthesized Aperture

2018 ◽  
Vol 2018 ◽  
pp. 1-7
Author(s):  
Oleg R. Kuzichkin ◽  
Dmitriy I. Surzhik ◽  
Gleb S. Vasiliev ◽  
Igor A. Kurilov ◽  
Nikolai V. Dorofeev
Keyword(s):  
Frequency Synthesizer ◽  
Phase Locked Loop ◽  
Frequency Synthesizers ◽  
Automatic Compensation ◽  
Direct Digital Synthesizer ◽  
Reference Oscillator ◽  
Noise Characteristics ◽  
Hybrid Frequency ◽  
Multichannel Systems ◽  
Phase Distortions

The noise characteristics of multichannel systems of forming signals based on hybrid frequency synthesizers with automatic compensation of phase distortions of direct digital synthesizers, which are used in the composition of georadars with synthesized aperture, are investigated. It is established that the phase noise of the output signals of the formers at the 1 kHz detuning from the carrier oscillation at the output frequencies of the devices in the range from 500 to 3500 MHz is characterized by a level of minus 100 - minus 130 dB. In this case, the circuit of the signal former based on a hybrid frequency synthesizer with direct digital synthesizer as a reference oscillator of a phase locked loop is characterized by the worst noise characteristics but with the highest degree of autocompensation (about 13 dB). Conversely, the circuit of the signal former based on a hybrid frequency synthesizer with direct digital synthesizer as a support generator of the phase-locked loop has the best phase noises level from the considered variants of devices and least degree of autocompensation (about 6 dB).

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