Measurement bandwidth 200 MHz *Īs the receiver is swept across the display frequency range, the LO is adjusted and powers measured in accordance with the table below: To reduce spurious outputs, Port 1 is terminated with a 50 Ohm match.įigure 1: Filtered signal 100 MHz and its harmonics. The output power of the Port 1 stimulus is set to 0 dBm, so that S21 corresponds to the power measured in dBm. Figure 1* shows the 804/1 VNA screen during analysis of a signal sent to Port 2 at 100 MHz, with an input level of -3 dBm and second harmonic attenuation of 80 dB, over the bandwidth from 1 MHz to 201 MHz. When measuring the upper LO, the displayed frequency is:įor Full-Size 304/1 fIF=10.7 MHz. When foutput falls in the IF bandwidth, this component will be amplified and displayed.

In general, the mixer output frequency is:įoutput=S*fsignal+G*fLO, where S and G are … -3, -2, -1, 0, 1, 2, 3,… As the first VAN receiver’s IF is normally not very high in frequency and is considerably lower in frequency than the sweep bandwidth, these distortion products can fall within the VNA frequency range. As a result, LO frequency harmonics are at higher levels than typically found in a SA receiver. To increase the stability of the first mixer conversion gain and to decrease its dependence on the LO power, the first mixer of a VNA receiver is normally operated at a point where the LO is close to saturation. The main difference between a VNA receiver and a classic spectrum analyzer (SA) receiver is that the VNA receiver has less attenuation of its own spurious responses, or spurs, especially the mixing products of the first mixer. In some cases, a VNA receiver can be used for the purposes of simplified spectrum analysis, which might include detection of self-excitation, determination of signal power and harmonic level, or spectrum deviation from an expected reference spectrum, among other parameters. Copper Mountain Technologies produces several VNA models including the Full-Size 304/1 VNA with a frequency range of 100 kHz to 3.2 GHz and 804/1 VNA with a frequency range of 100 kHz to 8.0 GHz. These instruments contain stimulus signal sources and receivers with one or more frequency converters.

Vector network analyzers (VNAs) are widely used in research, manufacturing, and service environments.

Spectrum network analyzer