Surface acoustic wave devices are now widely used for monitoring physical quantities such as temperature or stress. The intrinsic radio-frequency (RF) nature of these devices makes them ideal for wireless and passive sensor applications. We develop an interrogation unit following the principles of a frequency sweep network analyzer. The wireless interrogation of the resonance frequency of acoustic resonators induces the additional necessity of switching on and off the radiofrequency RF emission in a manner similar to that used in RADARs to comply with the regulations in the 433.4MHz, 1.7MHz wide, European ISM band. We assess the interrogation range, as well as the accuracy of the measurement and we develop various software strategies enabled by the fully digital nature of the radiofrequency RF synthesis chain. We particularly demonstrate the advantage of using different strategies depending on measurement application. The first strategy we have selected for interrogating narrow-band devices is a slow sweep of a frequency source with a spectral response narrower than that of the passive acoustic resonators. The basic principle is similar to that used by network analyzers, although the wireless link induces an additional constraint, namely the alternation of emission and reception phases as used in RADAR strategies with unique improvements such as emitting a probe pulse with a spectral width narrower than the resonance width at half height. We have presented previously [1] the digital processing steps used to improve the resonance frequency identification resolution, using a second-order polynomial fit. However, although a frequency-sweep network analyzer approach reduces the requirements in terms of sampling rate and memory capacity, the global interrogation duration is increased due to the many frequency steps required for accurately identifying the resonance frequency. Considering that each interrogation step requires 60μs and 128 steps necessary to find two resonant frequencies, 7.7ms is necessary to get a measurement. An alternative approach uses a feedback control to track the resonance frequency. Therefore, 3 interrogation points are enough to locate the resonant frequency, providing a measurement in 360μs. Once initialized, this three probe pulses strategy allows for detecting the resonance frequency with sub-100Hz resolution in the 434MHz ISM band. The second strategy uses a frequency-modulation-based interrogation strategy [2]. The conversion of frequency modulation to amplitude modulation by radiofrequency resonators hence reveals an accurate way to determine the resonance frequency of wireless passive sensors. Along this strategy, an interrogation strategy has been developed exploiting the cancellation of an amplitude modulated signal resulting from the conversion of the FM-to-AM conversion via the transfer function of the resonator. A feedback loop control based on this approach yields a resonance frequency detection with sub-25Hz resolution in the 434MHz ISM band with an acquisition rate around 1Hz. The third strategy is using a Universal Software-Radio Peripheral (USRP) running the GNURadio software to detect resonance frequencies by Fourier transform [3]. We compare the three strategies concerning accuracy, refreshing delay, detection distances and cost issues.