The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
We report a novel method for multichannel transmission delay measurement in optical fibers. The fiber transfer delay measurement is converted into frequency measurement. As a key technique, a simple ambiguity resolving process based on phase discrimination and frequency locking is used to overcome the contradiction between measurement accuracy and system complexity. A real-time calibration method...
We present two RF frequency dissemination methods (active and passive phase fluctuation compensation) for branching network. For the active one, the phase noise compensation function placed at the client site. One transmitting module hence can be linked with multiple client sites. For the passive one, without any phase control on the disseminated rf signals or usages of active feedback loop, the highly...
Microwave frequency standards based on ions are promising as the next generation atomic clocks. This paper reports the recent progresses of the microwave frequency standard based on laser-cooled 113Cd+ ions developed at Tsinghua University. Based on the current experimental setup, the ground-state hyperfine splitting of 113Cd+ is measured with higher precision and a better short-term frequency stability...
Partial discharges (PDs) are small electrical sparks that can occur in insulation systems in high-voltage equipment, and if it is kept for a long time, electric equipment and power grid will become very dangerous. Switchgears are the key equipment in the distribution power network. In this paper, by using artificial defect models in the laboratory, partial discharge test experiments based on transient...
We report on the progress of room-temperature operating, continuous-wave, tunable n-i-pn-i-p superlattice THz photomixers, compatible with 1.55 ??m telecom laser systems. An output power of 0.2 ??W at 1 THz has been achieved at a photocurrent of 9.4 mA, using a broadband antenna. The spectral power is at a level where high resolution spectroscopy becomes attractive. This is demonstrated by measuring...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.