Aufrufe
vor 4 Monaten

5-2018

Fachzeitschrift für Hochfrequenz- und Mikrowellentechnik

RF & Wireless allows

RF & Wireless allows designers to simulate 5G device under test (DUTs) in the Verizon downlink system and, alternatively, perfom error vector magnitude (EVM) and adjacent channel power ratio (ACPR) measurements. VSS VZ5G Downlink System Test Bench This application example demonstrates the VZ5G downlink transmission, which includes the physical broadcast channel (PBCH), physical downlink control channel (PDCCH), and physical downlink shared channel for data (PDSCH). The corresponding transmitter and receiver have already been set up, along with a behavioral amplifier DUT in between, as shown in Figure 1. The example has been configured to enable the user to perform various measurements. Figure 2 is a 100-MHz-wide signal before and after the DUT. Some spectral regrowth can be seen at the output of the spectrum. Some complementary cumulative distribution (CCDF) measurements have been set up in Figure 3, where the input and output to the DUT are shown. There is also a parallel power sweep measurement being performed on the signal operating on the AM-to-AM curve. The IQ constellation plot in Figure 5 shows the received demodulated IQ constellation for both the xPDCCH and xPDSCH. Figure 6 shows ACPR measurements at the 100 MHz and 200 MHz offset, which represent the channels for the VZ5G specification. The EVM versus input power and output power sweep measurement in Figure 7 shows the EVM characteristics as a function of output power. By replacing the DUT element in the diagram with the user’s DUT element of choice, this example can be quickly turned into a VZ5G-based test bench to evaluate system performance according to VZ5G specifications (Figure 8). Conclusion The VZ5G downlink system test bench within VSS enables designers to simulate 5G DUTs in the Verizon downlink system and also perform EVM and ACPR measurements. Because VZ5G specifications are in the early stages and therefore changing constantly, the current implementation in VSS will be updated according to developments. The advantage of the VSS signal generator is that it is built from basic building blocks, so when specifications change, the parameters in the root blocks can be updated without having to change hard code. When final specifications are made, the current VSS signal channel model (SCM) in the 5G channel model will be updated to the final configuration defined in 3GPP. ◄ MIL-DTL (ML) Series Power Dividers & Couplers MECA Electronics’ latest New Product Offering, ML series Power Dividers and Couplers designed to meet applicable portions of MIL-DTL-23971, MIL-DTL-15370 and MIL- STD-202. These models are designed for precision electrical performance, high reliability and intended for use in harsh environments from low orbit space & satellite to high altitude defense applications. These models are available with our standard screening process which incorporates a level of thermal screening combined with verification of electrical and mechanical performance features. In addition they are also available with enhanced levels of screening for qualification and verifications as required. To request add the ML prefix to any 80X series Power Divider or 750,765 or 780 series Couplers. Broadband 4-Way SMA Power Dividers 500 MHz – 6.000 GHz MECA Electronics’ latest New Product Offering, 4-way compact broadband of Power Dividers covering 0.500-6.000 GHz (804-2-3.250) encompassing Public Safety through ISM bands. With typical performance of; VSWR’s of 1.30:1 & 1.25:1, Isolation 21 dB, Insertion Loss 1.5 dB and exceptional Amplitude & Phase Balance of 0.6 dB & 10 degrees max. This is in addition to the family of 2, 4, 8 & 16 way splitters in various connector styles and IP60 & 67/68 ratings. Broadband 2-Way TNC Power Dividers 500 MHz – 6.000 GHz MECA Electronics’ latest New Product Offering, 2-way compact broadband of Power Dividers covering 0.500-6.000 GHz (802-6-3.250) encompassing Public Safety through ISM bands. With typical performance of; VSWR’s of 1.20:1 & 1.25:1, Isolation 22 dB, Insertion Loss 0.6 dB and exceptional Amplitude & Phase Balance of 0.3 dB & 5 degrees max. This is in addition to the family of 2, 4, 8 & 16 way splitters in various connector styles and IP60 & 67/68 ratings. Broadband 4-Way BNC Power Dividers 500 MHz – 6.000 GHz MECA Electronics’ latest New Product Offering, 4-way broadband of Power Divider covering 0.500-6.000 GHz (804- 8-3.250) encompassing Public Safety through ISM bands. With typical performance of VSWR’s of 1.30:1 & 1.40:1, Isolation 21 dB, Insertion Loss 1.2 dB and exceptional Amplitude & Phase Balance of 0.6 dB & 10 degrees max. This is in addition to the family of 2, 4, 8 & 16 way splitters in various connector styles and IP60 & 67/68 ratings. ■ MECA Electronics, Inc. www.e-MECA.com 72 hf-praxis 5/2018

RF & Wireless Switchable Oscillators Offer Frequency a la Carte Euroquartz has launched a new range of switchable crystal oscillators offering users the ability to provide four different frequencies. The new QuikXO HC_JF series oscillators are available in frequencies from 15 to 2100 MHz with a choice of outputs including LVCMOS (up to 250 MHz), LVPECL, LVDS and CML differential. High current steering logic (HCSL) differential outputs are available for frequencies up to 700 MHz. Integrated phase jitter performance of 150 fs maximum makes these crystal oscillators particularly suitable for high frequency applications. QuikXO HC_JF series crystal oscillators are available at low cost and can be delivered in days for prototypes with a choice of supply voltages – 1.8, 2.5 or 3.3 V – across the range apart from LVPECL with 2.5 and 3.3 V only. Customers can select any four frequencies in the range and the oscillator can switch to each as required, useful in frequency bus distribution applications on multi-processor boards where several frequencies are required for the different processors. The four chosen frequencies can all be synchronised from the single crystal oscillator instead of trying to sequence multiple clocks to achieve switching in of the various processors. Frequency selection is made using two logic control pads FS0 and FS1 to provide the four user selectable frequencies with frequency select timing of 2.5 ms maximum. Frequency stability specifications of ±25, ±50 and ±100 ppm over both commercial (-10 to +70 °C) and industrial (-40 to +85 °C) temperature ranges are available as standard. Other specifications include maximum ageing of ±3ppm in first year, duty cycle of 50% ± 5%, rise times of 0.35 ns maximum and current consumption from 62 to 99 mA typical. RoHS compliant, the new QuikXO HC_JF crystal oscillators are housed in industry standard 8-pad, 7 x 5 mm surface mount packages. ■ Euroquartz, Ltd. www.euroquartz.co.uk New EMI Components Manufacturers of electronic equipment for Hi-Rel applications often struggle to meet stringent EMC and safety standards. Knowles Precision Devices (KPD) has a range of EMI components, under the SYFER brand, that particularly appeal to designers in the medical implantable and space sectors as well as industrial, automotive, aerospace and telecom applications. The increasing use of SMD filters over conventional panel mounted filters has simplified assembly methods, reduced production costs and enabled smaller volumetric efficiencies to be gained giving a greater choice of options to the designer - particularly shorter lead-times for development samples. KPD continues to refine existing ranges, explore new ones and bring on board new materials, like lead free dielectrics. For example, the SYFER E01 and E07 ranges of feed through MLCC ‘C’ filters now have extended working voltages from 25 to 200 Vdc, and in certain cases up to 500 Vdc. This will significantly broaden the market for these devices. These surface mount EMI filter 3 terminal chip devices are designed to offer reduced inductance compared to conventional MLCC’s when used in signal line filtering. The filtered signal passes through the chip’s internal electrodes with the ‘noise’ filtered to the grounded side contacts, resulting in reduced length noise transmission paths. Available in C0G/NP0 & X7R di electrics, in case sizes 0805 to 1812. Current ratings are 300 mA to 3 A with voltage ratings of 25 to 200 Vdc (500 Vdc in some case sizes). Particularly effective in replacing conventional array filters in medical implantable devices is the SYFER E03 (X2Y) range. Available in case sizes from 0805 to 2220 these are integrated passive devices featuring both common and differential mode capacitors in a single MLCC chip. C0G and X7R dielectric versions are both available options. X7R dielectric versions are available with KPD‘s proven FlexiCap termination which is strongly recommended for new designs. Ideal for both signal and power lines, and ensuring impressive EMI filtering performance, is the SYFER SBSP range of surface mount pi-filters. With a size of only a 1206 chip they offer an unbeatable combination of size and performance. Ideal for telecoms, power supplies and industrial electronic equipment. The operating temperature range of -55 to +125 °C ensures they are also suitable for mil/aerospace applications. The use of X7R and C0G ceramic dielectrics sees capacitance values from 22 pF to 150 nF with a 1 A current rating. They have working voltages up to 100 Vdc. ■ Knowles Precision Devices www.knowlescapacitors. com hf-praxis 5/2018 73