Question
Receiving the I and Q values via remote control. How are the I and Q values inserted into the data stream?
I/Q mode data transfer
Answer
Remote reading of I/Q data from the R&S FSV
The description explains the formats of the I/Q data readout in binary mode. The order of the I and Q information in the binary byte stream is specified by transfer format. Three different transfer formats have been specified.
The remote command for specifying the transfer format is
TRACe<n>:IQ:DATA:FORMat <Format>
These three transfer formats are named as follows:
COMPatible -> 512k I data samples, 512k Q data samples, 512k I data ......
IQBLock -> I data block, Q data block
IQPair -> I data sample, Q data sample, I data sample, Q data sample, I data ......
The drawing contains samples (not bytes). Four bytes contain the content of one sample.
In the case of data blocks 512k I data samples is: 512k samples = 512 * 1024 = 524288 samples
In the case of data blocks 512k Q data samples is: 512k samples = 512 * 1024 = 524288 samples
There are two different ways to initiate a data transfer: getting all data at once and getting the data in small quantities.
Getting all data at once: TRACe<n>:IQ:DATA?
Getting all data in small quantities: TRACe<n>:IQ:DATA:MEMory? <OffsetSamples>,<NoOfSamples>
The overall number of data bytes transferred via the interface is as follows:
L = H + s * b * i
L -> overall number of data bytes transferred
H -> length of header information (see header specification at the end of this note)
s -> number of samples
b -> always 4 because four bytes contain the content of one sample
i -> always 2 because one sample represents I data and Q data
Examples:
===================================================================================================
Transfer format: COMPatible
Number of measured samples: 10
Number of bytes to transfer: 10 samples * 4 * 2 + header = 80 bytes + header
------------------------------------------------------------------------------------------------------------
Using TRACe<n>:IQ:DATA?
The data stream contains: Header
40 byte I data
40 byte Q data
------------------------------------------------------------------------------------------------------------
Using TRACe<n>:IQ:DATA:MEMory? <OffsetSamples>,<NoOfSamples>
TRACe<n>:IQ:DATA:MEMory? 0, 3
The data stream contains: Header
12 byte I data
12 byte Q data
TRACe<n>:IQ:DATA:MEMory? 3, 3
The data stream contains: Header
12 byte I data
12 byte Q data
TRACe<n>:IQ:DATA:MEMory? 6, 3
The data stream contains: Header
12 byte I data
12 byte Q data
TRACe<n>:IQ:DATA:MEMory? 9, 1
The data stream contains: Header
4 byte I data
4 byte Q data
==============================================================
==============================================================
Transfer format: COMPatible
Number of measured samples: 700000
Number of bytes to transfer: 700000 samples * 4 * 2 + header = 5600000 bytes + header
------------------------------------------------------------------------------------------------------------
Using TRACe<n>:IQ:DATA?
The data stream contains: Header
2097152 byte I data
2097152 byte Q data
702848 byte I data
702848 byte Q data
------------------------------------------------------------------------------------------------------------
Using TRACe<n>:IQ:DATA:MEMory? <OffsetSamples>,<NoOfSamples>
TRACe<n>:IQ:DATA:MEMory? 0, 5000
The data stream contains: Header
20000 byte I data
20000 byte Q data
TRACe<n>:IQ:DATA:MEMory? 5000, 600000
The data stream contains: Header
2097152 byte I data
2097152 byte Q data
302848 byte I data
302848 byte Q data
TRACe<n>:IQ:DATA:MEMory? 605000, 95000
The data stream contains: Header
380000 byte I data
380000 byte Q data
===================================================================================================
===================================================================================================
===================================================================================================
===================================================================================================
Transfer format: IQBLock
Number of measured samples: 10
Number of bytes to transfer: 10 samples * 4 * 2 + header = 80 bytes + header
------------------------------------------------------------------------------------------------------------
Using TRACe<n>:IQ:DATA?
The data stream contains: Header
40 byte I data
40 byte Q data
------------------------------------------------------------------------------------------------------------
Using TRACe<n>:IQ:DATA:MEMory? <OffsetSamples>,<NoOfSamples>
TRACe<n>:IQ:DATA:MEMory? 0, 3
The data stream contains: Header
12 byte I data
12 byte Q data
TRACe<n>:IQ:DATA:MEMory? 3, 3
The data stream contains: Header
12 byte I data
12 byte Q data
TRACe<n>:IQ:DATA:MEMory? 6, 3
The data stream contains: Header
12 byte I data
12 byte Q data
TRACe<n>:IQ:DATA:MEMory? 9, 1
The data stream contains: Header
4 byte I data
4 byte Q data
==============================================================
==============================================================
Transfer format: IQBLock
Number of measured samples: 700000
Number of bytes to transfer: 700000 samples * 4 * 2 + header = 5600000 bytes + header
------------------------------------------------------------------------------------------------------------
Using TRACe<n>:IQ:DATA?
The data stream contains: Header
2800000 byte I data
2800000 byte Q data
------------------------------------------------------------------------------------------------------------
Using TRACe<n>:IQ:DATA:MEMory? <OffsetSamples>,<NoOfSamples>
TRACe<n>:IQ:DATA:MEMory? 0, 5000
The data stream contains: Header
20000 byte I data
20000 byte Q data
TRACe<n>:IQ:DATA:MEMory? 5000, 600000
The data stream contains: Header
24000000 byte I data
24000000 byte Q data
TRACe<n>:IQ:DATA:MEMory? 605000, 95000
The data stream contains: Header
380000 byte I data
380000 byte Q data
===================================================================================================
===================================================================================================
===================================================================================================
===================================================================================================
Transfer format: IQPair
Number of measured samples: 10
Number of bytes to transfer: 10 samples * 4 * 2 + header = 80 bytes + header
------------------------------------------------------------------------------------------------------------
Using TRACe<n>:IQ:DATA?
The data stream contains: Header
4 byte I data
4 byte Q data
4 byte I data
4 byte Q data
........
........
4 byte I data
4 byte Q data
Overall, there are 40 byte I data and 40 byte Q data
------------------------------------------------------------------------------------------------------------
Using TRACe<n>:IQ:DATA:MEMory? <OffsetSamples>,<NoOfSamples>
TRACe<n>:IQ:DATA:MEMory? 0, 3
The data stream contains: Header
4 byte I data
4 byte Q data
4 byte I data
4 byte Q data
4 byte I data
4 byte Q data
TRACe<n>:IQ:DATA:MEMory? 3, 3
The data stream contains: Header
4 byte I data
4 byte Q data
4 byte I data
4 byte Q data
4 byte I data
4 byte Q data
TRACe<n>:IQ:DATA:MEMory? 6, 3
The data stream contains: Header
4 byte I data
4 byte Q data
4 byte I data
4 byte Q data
4 byte I data
4 byte Q data
TRACe<n>:IQ:DATA:MEMory? 9, 1
The data stream contains: Header
4 byte I data
4 byte Q data
==============================================================
==============================================================
Transfer format: IQPair
Number of measured samples: 700000
Number of bytes to transfer: 700000 samples * 4 * 2 + header = 5600000 bytes + header
------------------------------------------------------------------------------------------------------------
Using TRACe<n>:IQ:DATA?
The data stream contains: Header
4 byte I data
4 byte Q data
4 byte I data
4 byte Q data
4 byte I data
4 byte Q data
......
......
4 byte I data
4 byte Q data
Overall, there are 2800000 byte I data and 2800000 byte Q data
------------------------------------------------------------------------------------------------------------
Using TRACe<n>:IQ:DATA:MEMory? <OffsetSamples>,<NoOfSamples>
TRACe<n>:IQ:DATA:MEMory? 0, 5000
The data stream contains: Header
4 byte I data
4 byte Q data
4 byte I data
4 byte Q data
4 byte I data
4 byte Q data
......
......
4 byte I data
4 byte Q data
Overall, there are 20000 byte I data and 20000 byte Q data
TRACe<n>:IQ:DATA:MEMory? 5000, 600000
The data stream contains: Header
4 byte I data
4 byte Q data
4 byte I data
4 byte Q data
4 byte I data
4 byte Q data
......
......
4 byte I data
4 byte Q data
Overall, there are 24000000 byte I data and 24000000 byte Q data
TRACe<n>:IQ:DATA:MEMory? 605000, 95000
The data stream contains: Header
4 byte I data
4 byte Q data
4 byte I data
4 byte Q data
4 byte I data
4 byte Q data
......
......
4 byte I data
4 byte Q data
Overall, there are 380000 byte I data and 380000 byte Q data
===================================================================================================
===================================================================================================
===================================================================================================
===================================================================================================
===================================================================================================
Specification of the header of a binary data stream:
#45168xxxxxxxx
The ASCII character # introduces the data block. The next number indicates how many of the following digits describe the length of the data block. In the example, the 4 following digits indicate a length of 5168 bytes. The data bytes follow. During the transmission of these data bytes, all End or other control signs are ignored until all bytes are transmitted.
This format only supports a byte count up to 9 digits for the number of bytes. For more than 999999999 bytes, the following additional format is used.
#(1100000000) xxxxxxxx
Byte length count if put in brackets. In the example, the byte count indicates a length of 1,100,000,000 bytes. The data bytes follow after the closing bracket.
