Principle of Operation

The block diagram of the Analyzer is represented in Figure 1.

The Analyzer Unit consists of a source oscillator, local oscillator, source power attenuator, and a switch connecting the source signal to two directional couplers, which are connected to the Port 1 and Port 2 connectors. The incident and reflected waves from the directional couplers are passed into the mixers, where they are converted to first IF (10.7 MHz for Planar models; 0.4 MHz for S models; 7.6 MHz for Cobalt models) and are passed further to the 4-Channel receiver. The 4-Channel receiver, after filtering, digitally encodes the signal and supplies it for further processing (filtration, phase difference estimation, magnitude measurement) by the signal processor. The IF measurement filters are digital and have bandwidths of between the instrument minimum (1 Hz for Planar and Cobalt models; 10 Hz for S models) to instrument maximum (30 kHz for Planar and S models; 1MHz for Cobalt models). Either port of the Analyzer can be a source of the tested signal as well as a receiver of the signal transferred thought the DUT. If Port 1 is a source, Port 2 will be a receiver. The definition “incident and reflected” wave is correct for the port when it is a source of the test signal. The combination of the assemblies of directional couplers, mixers and 4-Channel receiver forms four similar signal receivers.

An external PC controls the operation of the components of the Analyzer. To perform S-parameter measurements, the Analyzer supplies the source signal of the assigned frequency from one of the ports to the DUT, then measures magnitude and phase of the signals transmitted through and reflected by the DUT, and finally compares these results to the magnitude and phase of the source signal. Figure 1 Analyzer Block Diagram

Planar 814/1 has adjustable ports configurations with direct access to the receivers. This adjustable port configuration with direct access to the receivers of the VNA provides for a variety of test applications requiring wider dynamic and power range. Direct receiver access enables testing of high power devices. Additional amplifiers, attenuators, various filters and matching pads for each of the ports can be introduced in reference oscillator and receiver path to ensure the optimal operation mode of the receivers and the DUT, close to the real.