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.
Recent improvements and continuous research on accurate clocks and frequency standards require the study of suitable tools and techniques for frequency transfer that minimize the added noise and allow fully exploiting these clocks in metrology applications. Different experiments performed during the last decade validated fiber links as the most performing tool for frequency transfer, reaching a statistical...
A two-channel AC voltage source based on digital synthesis is reported. We present measurement results of some of the key properties at 1 kHz with applications like digital impedance bridges in mind. Measurements show that amplitude ratio of the channels has a stability (Allan standard deviation) of one part in 108 for a 30 min measurement. The phase difference between the channels is also stable...
A two-channel analog-to-digital converter was used to investigate the noise of the cryogenic quantum Hall resistance. Without applied current, only thermal Johnson-Nyquist noise is present. With applied current, excess noise due to dissipation bursts appears which dramatically increases with the non-integer fraction of the filling factor.
The correlation method is used in Johnson noise thermometry to reject noise added by the amplifiers employed. The rejection is not perfect and a systematic error in the temperature reading appears. A method to estimate such error, based on mixed analytical-numerical simulation of sensor and amplifiers, is outlined and applied to compare two different amplifiers designed for the INRIM Johnson noise...
The absolute Johnson noise thermometer (JNT) being developed at INRIM traces temperature measurements to electrical units. A pseudorandom noise signal is employed for calibration: the traceability of its RMS value was given by commercial AC voltmeter. To improve the measurement accuracy, a primary ac-dc transfer method with a multi-junction thermal converter, is presently implemented. First results...
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.