Keithley Instruments’ Model 2800 RF Power Analyser is engineered specifically for production test of wireless phones, RFIC power amplifiers, and related RF devices designed to the AMPS, cdmaOne, North American digital cellular (TDMA), GSM, GPRS, EDGE, PDC, cdma2000 1X, cdma2000 3X, and W-CDMA standards.
It is an alternative to general-purpose, display-based spectrum analysers and communication test sets, which Keithley claims are relatively slow, large, more expensive, and better suited to research and development applications.
Industry standards for wireless phone transmission require measuring power in certain specified bandwidths. A cellular phone power calibration test routine may require many power measurements per frequency band, which must be performed on every phone leaving the production line. Multi-mode (multi-standard) and multi-frequency band phones require power measurements for each operating mode and frequency band.
The Model 2800 is designed for measuring power in the cellular bands, the higher DCS and PCS bands, and the WCDMA (UMTS)/cdma2000 bands. In addition to measuring power in defined primary transmission channels, it can measure spurious or interfering power at specific frequency offsets, like the upper and lower channels adjacent to the primary channel, as well as the upper and lower alternate channels. Adjacent channel power measurements let test engineers determine adjacent channel power ratios (ACPR), which are needed to ensure wireless devices and components don’t exceed the limits for spurious emissions/interference defined by industry standards.
The Model 2800 also measures carrier frequency so manufacturers can verify that their device-under-test is transmitting at the proper frequency.
The instrument can make a 1.23MHz bandwidth cdmaOne primary power measurement and transfer the measurement to a computer in 6msec. It can measure a 3.84MHz bandwidth primary channel measurement in 10msec, and can make power measurements on consecutive 577µs GSM pulses occurring every 4.6msec. It can make a cdmaOne primary power measurement, an upper adjacent power measurement, lower adjacent power measurement, upper alternate power, and lower alternate power – a total of five measurements – in only 23msec (including PC command time and data transfer to the PC time). A GSM primary power measurement and two spurious power measurements take only 14msec. These measurement times are 4 to 10x faster than those from competitive methods, according to Keithley.
Test speed is further enhanced by the fact that the Model 2800 includes setups for each of the cellular phone standards. One command programs the Model 2800 to prepare to make power measurements based on a specific standard. Overall, it takes only five commands to set up the instrument and to make a primary power measurement and four alternate/adjacent channel measurements.
For wireless device testing, the Model 2800 has measurement performance that exceeds that of general-purpose programmable bandwidth measurement devices such as spectrum analysers. The Model 2800 provides a more than sufficient dynamic range. For example, in applications involving cdmaOne, the Model 2800 has a dynamic range of greater than 90dB. Basic accuracy is +/-0.3dB. Repeatability is 0.05dB for CW signals and 0.1dB for complex modulated signals. VSWR is less than 1.3:1.