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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.Using our legacy API, the device can be configured to use the 2.9 MHz IF (hung mixer mode). You would have to use a higher frequency than 5 MHz (something like 15 MHz at least). I’m not sure it would get you significantly better numbers, but it might give you a few more dB.
There is probably enough RF-to-IF leakage in the mixer that you could use this mode (SHAPI_Configure, use 2.9 MHz IF set to true) and inject your signal directly at 2.92 MHz (at a higher amplitude). This is the closest to direct ADC access the SA series offers.
These are just my thoughts, and may not work, but if you give it a try let me know what you find. The BB60C has more direct ADC access, but realistically, the SM200A would be the ideal choice.
The BB60C has a built-in DC block. We correct amplitude down to 9 kHz, but there is a lot of VSWR below 100 kHz, making scalar measurements difficult
Mehran,
We typically need to evaluate the market demand for something like this before we commit to implementing it. And then there is a timeline for feature requests. It rarely happens in a few days unless you have placed a very large order and it is a very simple feature.
If other users chime in requesting a similar feature, the priority gets bumped up. Otherwise, we will evaluate it and make a decision as time permits.
Because of the BB60C architecture, its phase noise, especially at low frequencies (e.g. below 1 GHz) is not very good. So we decided to disable phase noise measurements rather than provide poor results.
The SM200A is recommended for phase noise measurements inside 100 kHz offset. The SA44B can make pretty good phase noise measurements as well, especially outside 100 kHz offset.Pritam,
Our API supports a maximum of 8 per computer. Keep in mind that the USB high speed bus is a shared bus, so you probably can’t even have 8 SA44B devices all streaming at the same time, unless you were decimating the data heavily.A possible setup, if you need 24 USB-SA44B’s simultaneously streaming to one PC, would be to have 7 PCs in a network. Use 6 PCs to connect to 4 SA44B’s each, and each stream their data to the 7th PC. It would be a bit of a project, but any project that requires 24 spectrum analyzers is going to be a bit of work anyway.
Yes, the VSG25A would work well for this.
Here is a picture. There is a connector that comes up through the case to power the fans. There are 6 fans, each 23 dB(A). I believe it can be replaced by the user, since you do not have to open the main enclosure to replace them. The fans are kept off until the FPGA reaches a certain temperature (I believe 50C), and then they turn on (until the FPGA is below 30C), and I believe the fans turn off for phase noise measurements.
Let me know if you have more questions.Out of curiosity, what type of functions would you be interested in adding? Is it something many users would benefit from, or something specific to your application?