What are the details regarding the baseband capture memory for option N9020A-BBA, Analog Baseband I/Q Inputs on the N9020A MXA using the 89600 VSA sof
Capture memory at baseband is 500 MSa. The table below describes the various record lengths for a given capture bandwidth or span.
| 89600 Record Lengths (I+jQ mode) | ||||
|---|---|---|---|---|
| Capture Bandwidth | Sample Rate | Data Packing | Capture Samples | Record Length |
| 10 MHz | 12.8 MSa/s | 32 I and 32 Q | 250 MSa | 20 Seconds |
| 20 MHz | 25.6 MSa/s | 32 I and 32 Q | 250 MSa | 10 seconds |
| 40 MHz | 50 MSa/s | 32 I and 32 Q | 250 MSa | 5 Seconds |
| 80 MHz | 100 MSa/s | 16 I and 16 Q | 500 MSa | 5 Seconds |
The user can set the capture bandwidth also known as measurement span using the 89600 VSA software. The 89600 VSA software will then automatically set the sample rate. In most cases the sample rate is 1.28 X Capture BW.
For sample rates below 50 MHz, 32 bits real and 32 bits imaginary are stored to enable more dynamic range. This occurs because at lower sample rates the noise is reduced due to the lower capture bandwidths.
Note: Record length = Capture Samples/Sample Rate
Record Length Benchmarks:
- 200 second record length with a 1 MHz capture bandwidth (GSM/EDGE)
- 40 second record length with a 5 MHz capture bandwidth (W-CDMA)
- 20 second record length with a 10 MHz capture bandwidth (Mobile WiMax ®)