江苏ZVR，二手ZVR

The extremely low-noise and fast synthesizer in conjunction with an exceptionally large measurement bandwidth of up t o 26 kHz al l ows real - time result display. The ZVx measures not in t w o subsequent sweeps but at every frequency point in forward and backward direction and thus all four S-parameters - including system error correction. This ensures real-time display of fully corrected data even during alignments with reduced sweep speeds. The dynamic range of ZVx is more than 95 dB even at a high measurement rate of 25 sweeps/s and 10 kHz measurement bandwidth.

The high stopband and low passband attenuation of modern RF c o mponents place new demands on n e t w ork analyzers. Thanks to fundamental mixing, the useful dynamic range of Rohde & Schwarz n e t w ork analyzers is more than 25 dB better than with conventional sampling techniques. Because of the low-noise front end, Rohde & Schwarz n e t w ork analyzers attain a dynamic range of >130 dB, so transmission measurements on DUTs with extremely high stopband attenuation can be performed with high ac c uracy, even at low input levels.

Power calibration performed in the factory enables constant output power and high ac c uracy in the measurement of absolute input level over the full frequency range. This is particularly important for frequency-converting measurements and non-linear measurements on active c o mponents. Furthermore, frequency-dependent level variations of an external test setup can be measured and c o mpensated with the aid of the Power Calibration option.

The ZVx models are the first n e t w ork analyzers in this price class to simultaneously display up to four measurement traces with independent parameters (measured quantity, frequency range, bandwidth, etc). The large, active colour LCD with high refresh rate allows precise alignments without operator fatigue.

The n e t w ork analyzers are equipped with a PC board including interfaces for keyboard, mouse, printer, external monitor and WindowsNT as the operating system. In the PC mode, the internal hard disk can be ac c essed and PC programs executed on the ZVR. This function considerably simplifies operation, processing and result recording. The optional Ethern e t link, the integration of any printer driver and the execution of IEC/IEEE bus control programs on ZVR considerably extend the application range and performance. Complete setups, traces, numerical results, limit lines, calibration data, macros and screenshots can be stored on the hard disk or on floppy disks. The available formats (e.g. WMF, ASCII, Serenade....) allow problem-free import to Windows programs. The data can be processed in the ZVR with the aid of the internal PC.

 

Fast recording and processing of measured data and, in addition, an SCPI-conformal IEC/IEEE bus c o mmand set make all models of the ZVR family ideal for use in automatic measurement systems. All models are equipped with t w o IEC/IEEE bus interfaces as standard. One is used for analyzer control via an external PC, the other for controlling external devices, e.g. signal sources for intermodulation or mixer measurements, from the ZVR. Another optional IEC/IEEE bus interface is provided for the internal PC. Via this interface, IEC/IEEE control programs can be executed on the internal PC, thus enabling the ZVR to control itself or c o mplete test systems. The Ethern e t option allows data exchange and control via LAN.

The classic 12-term calibration method requires four calibration standards: Through, Open, Short and Match. The n a m e TOSM given to this method is an abbreviation of the standards‘ n a m es. A number of other modern calibration methods (TOM, TRM, TRL, TNA) are also provided in ZVR and ZVC. Unlike TOSM (12-term) they require only three different standards. Additionally, lines (L), reflecting one-ports with unknown reflection coefficient (R), matched attenuators (A) and t w o-port n e t w orks (N) with symmetrical reflection can be used. Due to its simplicity, TOM is the method rec o mmended for general applications. For calibration at frequencies up to 100 MHz it is not even necessary to connect an open circuit, and the ports may simply be left open. Thus a c o mplete t w o-port calibration can be performed with only t w o calibration standards. TOM allows also implicit verification so that errors caused by defective calibration kits or operating errors are excluded. This considerably enhances reliability in the laboratory and particularly in production.

With on-wafer measurements, measurements on PCBs or in fixtures it is difficult to design or specify suitable calibration standards at justifiable effort. This problem can be solved with the TNA and TRM calibration methods developed and patented by Rohde& Schwarz. With these methods the characteristics of the calibration standards need not be fully known. With TNA, for instance, a full t w o-port calibration can be performed with t w o standards: if reflection symmetry is provided at the reference planes, the calibration step with n e t w ork (N) does not require a standard to be connected, the test ports can just be let open. Just a through (T) with known length and a matched attenuator (A) are required.

The calibration effort is reduced to a minimum when the AutoKal option is used that requires only one simple through-connection.