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1. What is the frequency range of the NSI Panther Receiver? 2. What are the differences between the various sources NSI supports for the Panther receiver? 3. Can I use Agilent mixers with the DFC LO/IF Unit? 4. Can the DFC mixers be used with an Agilent 85309A? 7. What RF connector types are compatible with each other, or can cause damage when mated? 8. Should I be concerned about ESD damage using long coaxial RF cables? 9. How accurate is the open-ended waveguide probe model included in the NSI 2000 software? 10. What is the gain value and gain uncertainty for the NSI Open-Ended Waveguide Probes? 11. Is the NSI 2000 software capable of controlling a beam steering computer (BSC) during a scan? 12. What is included with the NSI-PNA-20 system? 13. What are the internal frequency band crossings for the Agilent PNA? 15. Are
waveguide mixers better than coax mixers? When should
they be used? 1. What is the frequency range of the NSI Panther Receiver? The Panther is an IF receiver, operating at 20 MHz. The Panther is typically paired with a distributed frequency converter system like the NSI-RF-5940 or the Agilent 85310, and with appropriate external sources, frequency converters, and mixers can operate from below 1 GHz up to higher than 100 GHz.
2. What are the differences between the various sources NSI supports for the Panther receiver? Click here for a chart comparing RF sources.
3. Can I use Agilent mixers with the DFC LO/IF Unit? This requires a NSI-RF-5949 mixer interface module. This module supports most mixer types, including waveguide mixers.
4. Can the DFC mixers be used with an Agilent 85309A? No, it's better to replace the 85309A with the DFC LO/IF Unit.
5. I want my RF system to automatically switch between Tx and Rx mode. Can NSI provide this capability? Yes. NSI has designed systems that support automatic Rx/Tx switching and band-switching, as well as various antenna configuration modes.
6. I have purchased a new RF cable with SMA(m) connectors, but have been unable to connect it to the Agilent 87301E coupler. What is the problem? The Agilent 87301E is a 50 GHz coupler with 2.4mm(f) connectors. The 2.4mm(f) connector is not compatible with the SMA(m) connector. See FAQ #7.
7. What RF connector types are compatible with each other, or can cause damage when mated? Click here to see the frequency ranges and compatibility of different RF connectors.
8. Should I be concerned about ESD damage using long coaxial RF cables? We occasionally hear reports of customers damaging expensive RF equipment by electrostatic discharge (ESD). This note outlines a method for avoiding one common cause of equipment damage. A major cause of ESD-related damage is discharge from the center pin of a coaxial cable upon connecting it to some active device. A coaxial cable is basically a capacitor when the ends are left open. If the center conductor carries any charge, it will go right through your mixer, PIN switch, or network analyzer when you connect it. To avoid damage to expensive equipment, ALWAYS discharge the center conductor of ANY coaxial cable before connecting it to another device. To discharge the center conductor, use one of these methods:
Get into the habit of discharging cables before connecting them – help avoid expensive ESD damage!
9. How accurate is the open-ended waveguide probe model included in the NSI 2000 software? The OEWG probe model is based on a NIST algorithm (Yaghjian-1983). The model provides a far-field prediction of an open-ended waveguide probe with an accuracy of approximately 0.15 to 0.4 dB over +/- 60 degrees in Elevation and Azimuth. Click here to see a comparison of the NSI2000 OEWG model with measured probe data.
10. What is the gain value and gain uncertainty for the NSI Open-Ended Waveguide Probes? The gain of the OEWG probes are typically in the range of 4 dBi to 6 dBi. NSI can provide optional probe calibration if accurate probe gain values are needed, and the gain calibration uncertainty will be approximately +/-0.15 dB. Contact NSI's sales department for additional information.
11. Is the NSI 2000 software capable of controlling a beam steering computer (BSC) during a scan? Yes, with open-loop (output only) control. The standard NSI 2000 software does not support BSC handshaking, but it can be added as an option. The standard open-loop capability can be configured to output a bit pattern (typically up to 8-bits, TTL output - more bits may be provided with customization), which may be used by the BSC to control pre-defined beam states. The open-loop timing may be verified using the NSI 2000 inner-loop timing (ILT) display capability. The ILT display shows all beam running at the defined switching rate so that amplitude, phase and SNR may be verified at a fixed XY position in the high energy region of the antenna. If there is a timing or interface problem, the measured data will exhibit erratic behavior. Full handshaking with the BSC requires a custom interface and typically involves technical coordination between NSI and the customer to define the hardware and software interfaces. Contact the NSI sales department for a quotation.
12. What is included with the NSI-PNA-20 RF System? The NSI-RF-PNA20 RF System includes the following elements. NSI-RF-PNA20-VNA includes: * Agilent
E8362B PNA Network Analyzer NSI-RF-PNA20-SYS includes: * NSI-RF-5918
Beam Controller
13. What are the internal frequency band crossings for the Agilent PNA? The
frequency range of the PNA covers several internal frequency
bands. The higher the PNA frequency switching speeds vary with frequency and PNA model.
14. For harmonic mixing systems with AUT transmit and probe receiving, is it better to locate the harmonic mixer at the probe, so the lower frequency LO signal passes through the rotary joint, rather than the high frequency RF signal which might be up to 50 GHz? Wouldn't this reduce amplitude and phase errors induced by the rotary joint? Yes, it is generally preferred to locate the harmonic mixer closer to the probe, however there are tradeoffs which must be considered that may be more important. If the mixer is between the probe and rotary joint, that means it must rotate with the probe, adding weight and mechanical complexity to the rotating probe carriage, and may require larger probe absorber coverage. Also, for systems with TX/RX reversal requirements, it is easier and more convenient to locate the mixer on the probe carriage where we may also mount a multiplier and directional coupler for the case where we are transmitting the high frequency from the probe. Regarding the RF performance, the effect of the rotary joint's phase wow on the signal will be the same whether the rotary joint is passing the LO or the RF signal, since any phase errors at the LO frequency are multiplied up at the mixer and will have the same overall affect on the resulting IF signal. The placement of the mixer between the probe and rotary joint can help reduce the signal sensitivity to the amplitude wow of the rotary joint, since the LO signal amplitude variation does not directly affect the resulting IF signal since the mixer is a non-linear device.
15. Are waveguide mixers better than coax mixers? When should they be used? Agilent and NSI coax mixers can be used up to 50 GHz, and are typically preferred over the waveguide mixers due to their lower cost and convenience of having a broadband device (typicallly 1 - 50 GHz). Agilent's waveguide mixers have been discontinued; these used fairly high harmonic numbers resulting in high conversion losses. Above 50 GHz, waveguide mixers are the only solution. Contact NSI Sales Dept for a system quote. |
