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Signal power tends to fade at higher frequencies, due to the scarcity of power at those frequencies in addition to propagation and transmission losses. But it still must be measured, especially as more applications trend toward higher frequencies—including millimeter-wave bands—to accommodate the growing number of wireless users and applications.
To address this need, Anritsu Co. developed the Power Master MA24507A power analyzer, which performs frequency-based measurements of power over a frequency range from 9 kHz to 70 GHz, and over as many as six frequency channels at one time for channel power monitoring. Essentially, it can be thought of as a combination spectrum analyzer and power meter—one that’s small enough to fit in a pocket.
The Power Master MA24507A (see figure) is designed to connect via Universal Serial Bus (USB) to a personal computer (PC) running the firm’s PowerXpert test software. It features a wide dynamic range, detecting signal power levels as low as –100 dBm and as high as +10 dBm at most frequencies (and as low as –90 dBm at 70 GHz).
Like a spectrum analyzer, operators are able to set a channel bandwidth around a center frequency of interest, the better to monitor power levels of known signals. With the PowerXpert software and its Channel Monitor mode, users can set as many as six frequency channels to monitor continuous-wave (CW) amplitude or channel power simultaneously.
This compact power analyzer, which connects to a computer through the USB port, delivers precise power measurements on as many as six channels from 9 kHz to 70 GHz.
The test software also provides a Power Hunter mode that detects the six highest signal CW amplitudes and their frequencies across a frequency range of interest. In this measurement mode, the instrument can be set to look for signals with power levels from –90 to +10 dBm for start frequencies from 9 kHz to 70 MHz at spans of 1 kHz to 20 MHz.
Ideal for the Field
The powerful analyzer fits in a package measuring just 6 × 3 × 1 in. and weighs less than 15 oz. It thus becomes a viable candidate, along with a battery-powered laptop computer, for over-the-air and in-the-field on-site testing such as channel monitoring or interference detection. The instrument includes a 1.85-mm coaxial (V) connector to cover the wide frequency range and maintains excellent frequency accuracy by means of an internal reference oscillator with stability of ±0.1 ppm. Unlike traditional benchtop power meters, no reference calibration is required; the instrument can remain active for continuous on-air measurements while maintaining full accuracy.
The Power Master MA24507A delivers typical amplitude accuracy of ±1.0 dB throughout its power measurement range, at temperatures from 0 to +50°C. It achieves relative power accuracy of ±0.3 dB across the full frequency range of 9 kHz to 70 GHz.
When speed is important, such as in production test applications, the MA24507A performs multiple measurements per second. By way of example: For channel power measurements at a 1-GHz center frequency and span of 20 MHz, the measurement speed is clocked at 20 measurements/s and 25 measurements/s for a CW signal. Even at a 1-GHz span around a 1-GHz center frequency (500 to 1,500 MHz), measurement speed is 10 measurements/s.
This pocket-sized analyzer makes it possible to get close to a signal source, or to find the most distant signal sources at extremely low detectable levels. With its multiple-channel measurement capability, it can perform adjacent-channel-power (ACP) measurements as well as channel monitoring over wide frequency spans. The PowerXpert software runs on computers with Microsoft Windows 7, 8.1, and 10 operating-system (OS) software.