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The TG124A is only rated to -15 dBm. The TG44A goes to -10 dBm, though.
We do test each unit at their rated output power. It’s a tricky test, because we measure harmonics (which can be high), and then total output power with a thermal power sensor, and then calculate power at the fundamental frequency.
We do guarantee their accuracy (e.g. -15 dBm at 100 kHz should read -13 to -17 dBm on a suitable RF power meter). If you can make an accurate measurement at the RF output connector, and it is out of tolerance, this would be covered under warranty. January 29, 2021 at 5:17 pm in reply to: Discontinuity issue in Scalar Network Analysis using SA44B + TG44A Did you put a 6 dB attenuator on both the TG and the SA? It should align fairly well.
If you want more dynamic range, you could amplify the TG output. A good amplifier that covers your frequency range would eliminate the effect of SWR on the TG side. A gain of 10-20 dB, followed by the device under test, followed by a 10-20 dB attenuator to the SA should preserve dynamic range and give you excellent return loss on both the input and output for your device under test.
January 28, 2021 at 10:07 am in reply to: Discontinuity issue in Scalar Network Analysis using SA44B + TG44A SY,
This is likely due to impedance steps in the TG and SA. Although our systems are 50 ohms nominal, the SWR is not great in spots. This can be largely mitigated with a 6 dB fixed SMA attenuator on the TG and SA. Their attenuation will calibrate out, and should make any discontinuities all but disappear as your return loss will improve by 12 dB.Tyang,
The BB60C or SM200 have trigger inputs. This can help overcome software latencies if your generator also outputs a trigger. I am not sure what you are trying to test with your 250 kHz burst, but if you need to know the delay through a device under test, the BB60C offers some additional capabilities. December 3, 2020 at 9:38 am in reply to: TG44 standalone application (Amplitude and Refefence Option) The output power ranges from -30 to -10 dBm. Values outside this range are not expected to change amplitude. Additionally, the step size is about 1 dB but it will snap to the nearest measured value, so a step size of 2 dB is sometimes required to get an amplitude change. For finer amplitude control, consider one of our VSGs.
If nothing is connected to the 10 MHz in/out BNC, select “unused”The protocol to simply configure a center frequency contains commands to directly set registers on about a dozen different chips, writes values to FIR filters to optimize IF flatness and image rejection at the frequency selected, and digital tuners to center the frequency of the I/Q data. The API handles all of this behind the scenes.
The SA44B is designed for narrow-band signal measurement. However, if the task is simply to measure the power at the LNB and adjust the dish for maximum power, the SA44B can work for this. The SA44B cannot provide power. A bias tee can be used to provide power, but you must use a DC block because the SA44B front end is DC coupled.
DDR,
We digitally tune, so the frequency resolution is limited to a double precision floating point number (sub-Hz resolution). If you are asking about the tuning of the LO itself, we tune in 125/16 MHz steps (7.8125 MHz), and digitally tune from there. September 1, 2020 at 9:35 am in reply to: Using 10 dB coupler for return loss measurement & 20 dB pad placement Yes, but the scalar system for return loss only has the dynamic range of your coupler’s directivity, which is less than 40 dB. So it is not recommended to “store 20 dB pad” for return loss, only insertion loss.
August 31, 2020 at 12:06 pm in reply to: Using 10 dB coupler for return loss measurement & 20 dB pad placement Jeremy,
Your coupler will work fine. For return loss measurements, there is no reason to “store 20 dB pad” because 50 dB of dynamic range is more than enough for a return loss measurement.
For return loss measurements, if you have 3-6 dB SMA attenuators around, putting one on the TG and one on the BB can improve SWR which will make the measurements more accurate.Michael, this looks like the 140 MHz SAW band pass filter in the BB60C. Most of the ripple should generally be removed in our corrections, but there can sometimes be a little residual ripple which is somewhat worse as the device is warming up. Once the BB60C is fully warmed up, this ripple may be smaller.
Hopefully this helps. If you are looking for amplitude deviations smaller than 0.5 dB, you may need to wait for the device to warm up for 30 minutes, and then use trace math or some other mechanism to subtract out this baseline trace.
For what it’s worth, you should not see this ripple in the SM200B/C. We do not use any SAW filters, so the IF is smooth.It’s a Cypress FX3 chip, CYUSB3014
Kaiser,
I see two possibilities here.
1) The sheer data rate of the SM200B is causing problems, or
2) When you installed the software, you also installed the FTDI driver for our SA44B, which is somehow incompatible with the VN-310.If you re-install the VN-310 driver does it help? If you use FTDI’s “CDM uninstaller” with the VID/PID of the VN-310, and then plug it in, does it help?
Matthew,
I have never seen that before, but if you can write a little code, parse the wav file, probably window the data, do an FFT, threshold detect (1 for above threshold, 0 for below threshold), invert the threshold array, inverse FFT, then scale. I am not aware of an application for this, but if you have one, something like this would be a good way forward.Geev,
The I/Q pattern memory is pretty short (2k samples), but yes, a short Gaussian waveform is possible. You can also look at 1001 tones with random phase relationship, which will have many of the same properties as bandwidth-limited Gaussian noise.For a better Gaussian white noise generator, consider the VSG60A.
Kefei,
There are a few ways to do this. You could record the sweeps in Spike (you may need an SM200 in real-time mode, span >160 MHz, for 1 ms sweeps).
For more control, you could simply record 1 second of I/Q and do your own windowed FFTs. With the SM200B, this would give you up to 2 seconds at 160 MHz span.
A third option is the waterfall spectrum plot in zero span mode. In this mode, the biggest limitation is probably the 1 second requirement. This would set a pretty low I/Q sample rate, since you are limited to a few million I/Q data points.Volker,
Yes, this is something we have discussed. It is not something we have scheduled at this point, but it is definitely something we hope to add in the future. It would probably not be one of our existing tracking generators, but something geared towards the frequency range and performance of the SM series.Gary,
There are a few things going on here. It sounds like you are aware there is no baseband reconstruction filter on the VSG25A. But we also apply an inverse sinc correction to the in-band data to flatten it.
PN9 is a PRBS9 sequence (linear feedback shift register) that basically repeats every 511 symbols. We upsample each symbol by a factor of 4 to produce 2044 I/Q samples, which get transmitted in a loop.
Even with no raised cosine filter, the upsample process will result in gaps in the sin(x)/x curve.
Hopefully this helps.If it helps there are schematics online. Typically a 1 Mohm input impedance to a non-inverting unity gain op amp, with a 50 ohm series resistor (or resistor to bring it to 50 ohms) on the output. You may want to add a ceramic [0.1 – 10] uF DC blocking cap, depending on your low frequency coverage needs.