Linear Technology DC426B, Быстрый старт

Страница: 3 / 11

3 of 10
LT5511 Upconverting Mixer Two-Tone Measurements for 1900MHz Band.
1. Connect all test equipment as shown in Figure 3.
Note: 1). A high quality combiner that provides 50-ohm termination on all ports and has
good port-to-port isolation should be used.
2). The two 3dB attenuators on the inputs of the combiner are used to further improve
source isolation.
2. Set the Power Supply output voltage to 5V, and set the current limit to 100mA.
3. Set the dipswitch SW1 (Enable) to 1. Mixer is in ENABLE mode.
4. Set the Signal Generator #1 to provide a 1950MHz, -10dBm, CW signal to the demo board
LOin port.
5. Set the Signal Generator #2 and #3 to provide two -5dBm CW signals to the demo board IFin
port—one at 50MHz, and the other at 51MHz.
6. Set the Spectrum Analyzer’s center frequency to 1899.5MHz. Perform input 3
rd
order
distortion measurement. (IIP3 = P1 + (P1 – P3) / 2 – Gc, where P1 is the lowest power level
of the two desired output tones at either 1899MHz or 1900MHz, P3 is the largest 3
rd
order
product at either 1898MHz or 1901MHz, and Gc is conversion gain. P1 and P3 are in units
of dBm, and Gc is in dB.)
Figure 3. Test Set-Up for Mixer Two-Tone Measurements
POWER SUPPLY
SPECTRUM
ANALYZER
SIGNAL
GENERATOR 1
SIGNAL
GENERATOR 3
∑
SIGNAL
GENERATOR 2
3dB PAD 3dB PAD