Free Standards Online
DIN EN 62761-2014 Guidelines for the measurement method of nonlinearity for surface acoustic wave (SAW) and bulk acoustic wave (BAW) devices in radio frequency (RF). 5 Nonlinearity measurement 5.1 Measurement equipment 5.1 .1 Signal generator and power amplifier In the setups shown in Figures 4-9, SGs shall possess the following properties: a) small nonlinearity, b) good short term stability (small frequency fluctuation), c) capability to synchronise with an external standard oscillation signal (usually 1 0 MHz). Requirements b) and c) are imposed to reduce the thermal noise level in the SA read as will be discussed later. When the use of Pas is needed, their choice is crucial. Namely, the output stage of the PA shall operate in the class A mode, and the nominal maximum output of PA shall be sufficiently larger than the value required for the measurement. For example, use of PAs with maximum output of 5 W seems appropriate for 500 mW output. Since thermal noise is also emitted from PAs, the use of PAs with too large maximum output power may result in an increase in the noise level in the SA read. 5.1.2 Spectrum analyser In the nonlinearity measurement, various spectrum components are simultaneously incident to the SA, and some of them may be much stronger than the target frequency component. Thus the SA shall possess good linearity and wide dynamic range. Since minimum detection level is determined by the noise level, SAs with low noise level is preferable. One may think that the vector network analysers (VNAs) can be used for this purpose. Since VNAs possess smaller linearity and dynamic range than SAs in general, applicability of VNAs might be limited. It should be noted that the thermal noise level in the SA read is inversely proportional to the resolution bandwidth (RBW), which is adjustable in conventional SAs. Namely, the noise level decreases in the form of 10 log(RBW) in dB. For the RBW reduction, fluctuation in the SG and/or SA frequencies shall be suppressed sufficiently. Or the fluctuation will result in decrease of the SA read. A convenient technique to reduce the fluctuation is synchronisation of all SGs and the SA. Current RF instruments generate RF signals using frequency synthesisers, and their output frequencies are given by the standard signal frequency f s (usually 1 0 MHz) times a digitally preset coefficient. Thus, provided that common f s is used in all...

Download Address

  • Download