A new digital-signal processing method for transmitter transient measurements

Transmitters employed in modern wireless communication systems generally incur in power and carrier transients. With the aim of limiting possible interference to other equipment operating in adjacent channels, the European standard on electromagnetic compatibility and radio spectrum matters imposes upper bounds on transmitter attack time. The standard also recommends a suitable test setup, in which a great number of instruments are involved. The authors propose an alternative digital-signal processing method for transmitter attack time measurements, based on time-frequency representations. The method simultaneously measures both power and frequency transients, and requires only a data acquisition system and a processing unit. Moreover, thanks to the use of band-pass sampling strategies already proposed by the authors, just a few thousand samples have to be acquired to measure the attack time. Optimal TFR parameter combinations are singled out through experimental tests on emulated signals, and examples of the application of the proposed method on actual RF transmitters are provided