Forum Replies Created
- Posts
Danz,
The Spike software allows you to configure the spur reject mode, as well as change RBW / span. Unfortunately, these are the only tools we have for the SA124B when it comes to spur mitigation.
You can look at the SM200A. If you require better spurious performance than the SA124B offers, this would be the next step. It is also much, much better at capturing periodic bursts of energy.
Jay,
No, I don’t think we have implemented this. You have to press Ctrl 1 thru Ctrl 9 to load a preset.The BB60C would be the minimum for this test (SM200A would be better). Zero span amplitude vs time and frequency vs time plots, probably with a decimation of 1 for pulse shape, and decimation of 8 to 64 for frequency measurements would be ideal (higher decimation would reduce the noise). You’re basically just looking at the phase change on each I/Q sample, converted to frequency.
Bittware,
I just wanted to jump in and ask if you had considered looking at the pulse in zero span mode with a video trigger? The SA44B won’t give you a great plot due to resolution and bandwidth limitations, but the BB60C would give you a great plot of your pulse’s amplitude over time.Iker,
Unfortunately, the VSG25A must be powered on after the computer is booted to work properly. You should be able to find a USB 2.0 hub that can be remotely powered down and back on. This may be the best workaround. I apologize for the inconvenience.Nolan,
The short answer is that the IF to I/Q data transition is a frequency shift to exactly match your requested center frequency, and amplitude corrections to remove ripple in the IF response. The I/Q data is typically easier to work with than the raw IF data, as phase information is a simple atan2 function, and power is simply I*I+Q*Q.Serpi,
Yes, we use an environmental chamber to test the units from -40 to +65 ambient for our correction data across temperature. Typically, the internal temperature runs around 8-9 C above ambient in the chamber, so the device corrections should be valid from about -32 to about +74 C internally reported temperature.I would add two resistors:
1) A 49.9 ohm series resistor for a 50 ohm output impedance
2) A 10k shunt resistor to ground after the DC blocking cap to bleed off residual DC.The SA44(A) has no preamplifier, poor spurious performance, and more limited RBW / VBW options depending on span.
The SA44B has gone through several improvements over the years. I would recommend getting something manufactured in 2013 or later for best performance.
You can check Mini Circuits for an acceptable coupler. You might have to get 2 or more to cover your frequency range. Look for connectorized models.
Dave,
A few things:
1) The attenuator we sell is only rated for 2 watts. You would need a 10-20 watt attenuator.
2) Typically a directional coupler is used to monitor transmit power. This way, you only lose a small amount of power and you can monitor it while in use. Depending on the “coupling loss (typically 20 dB) you may want additional attenuation. I would recommend aiming for between -10 dBm and 0 dBm to make decent measurements.There are a couple of options here. You could load an AWGN file as an arbitrary waveform. But the better way for most applications would be to use 1001 tones of random phase, spaced 10 kHz. This will have a CCDF curve that closely mimics AWGN, and will be flat across the desired 10 MHz band as it will automatically apply an inverse sinc correction.
bittware,
Real-time or zero span mode will both capture a 2 us pulse. For zero span mode, use video triggering. For real-time mode, you will want to use the maximum resolution bandwidth (RBW) and even still, the amplitude will read low due to the pulse width being less than the RBW time constant.
Preliminary tests on the compressed I/Q streaming indicated that we would end up with fewer channels than we had hoped for, and the interface would be prohibitively complex for most users, so we moved away from it, towards just adding additional memory for full 160 MHz I/Q captures.
Next year, we will have units available with this expanded memory. With video or frequency mask triggering, it should be straightforward to capture and analyze Bluetooth packets.The other thing to note is your circuit should have a 50 ohm output impedance. If it does not, the SA44B will load it down and the noise reading will be much lower.
Jubayer,
Setup for this type of measurement would be something like:
RBW 100 Hz, VBW 10 Hz, detector settings power, average. Center frequency 7 KHz, span 10 kHz. Reference level -50 dBm.
A 3.3 uF DC block should be reasonably flat down to 3 kHz or so.
Let me know if this works for you.Ed,
Depending on your serial number, there is a design flaw where under certain conditions the DC blocking cap on the preamp builds up a charge and blocks all signals. Any return path to ground for current will remedy this (including a non-zero attenuator setting).
We can issue an RMA to repair this as well (we add a small resistor). Contact support at signalhound dot com for more information. May 14, 2018 at 10:57 am in reply to: TG 124A with BB60A, AND suitability to use with other gear for immunity testing. Julian,
The BB60A will need firmware version 5 to be compatible. You can download it here: https://signalhound.com/support/product-downloads/bb60c-bb60a-downloads/The TG124A being used as a standalone generator, and amplified/modulated appropriately, should probably work for immunity testing. Depending on your needs, you may wish to low pass filter the TG output as it tends to have higher harmonics than a dedicated signal generator. You would probably want to automate it using our TG standalone API, which you can get from https://signalhound.com/products/usb-tg124a/
AJ,
I remember running into this before. I think this is the bug fix:
https://stackoverflow.com/questions/11775185/open-a-com-port-in-c-with-number-higher-that-9
Also, here:
https://support.microsoft.com/en-us/help/115831/howto-specify-serial-ports-larger-than-com9Maksym,
The power of 2 downsample factor sets the theoretical bandwidth that is available. For example, a downsample factor of 4 gives you 10 MSPS, which theoretically represents 10 MHz of bandwidth. But you should leave 20% for filter rolloff, etc. so generally bandwidth will be 40% to 80% of the total bandwidth based on your downsample rate.