The Hardware Design Of RF Power/Frequency Measurement Module

With the rapid development of mobile communications, the accurate measurement technology of the signal power and frequency has become the key link in the communication measurements. Basing on the existing power and frequency measurement techniques, this topic combines the power and frequency measurements together with the using of RF analog front-end circuit design. While it also puts forward the design of power/frequency measurement module based on Compact PCI bus, which realizes the measurements of the input continuous waves and the modulation pulse signals in real time.The absorption power test is adopted to achieve power measurement of the input signal. It realizes the conversion between the power of input signal and voltage by the chip AD8362 which is a true rms-responding power detector. The voltage value goes through the A/D converter and turns into the measurement of the signal power. To measure frequency, the prescale method is used to complete the expansion of frequency. After the input RF signal conditioning, frequency division and shaping, the equal precision frequency measuring methods based on the digital phase shift is used to measure the frequence by making full use of the digital logic flexibility and the internal PLL resources in FPGA.The FPGA is used as the core control measurement module, which is responsible for all the logic in the whole measurement module. The main functions of FPGA are to realizing synchronous measurement of power and frequency, storing the voltage data from the A/D converter,measuring the frequency of the input signal, and completing data communication with the host computer. Adopting the Compact PCI industrial bus achieves fast and reliable communication with the host computer. The using of special interface chip PCI9030 simplify the CompactPCI bus communication protocol, reduce the complexity of the design of interface circuit and speed up the development cycle of the measurement module. Logic inside the FPGA is designed using Quartus II platform, which can complete the whole design process from the input designing to the hardware configuration.Finally, the design module can work normally after jointly debugging with the corresponding driver and host computer. It verifies the feasibility of design scheme by realizing synchronous measurement of signal power and frequency and requested measurement range and precision. The measurement for power range is from-25 dBm to +10dBm. The measurement for frequency range is from 100 MHz to 2.7GHz.