![matlab 64-bit double precision matlab 64-bit double precision](https://i.stack.imgur.com/IVaTn.png)
If you use rawUnits=1 or rawUnits=2, you need to adjust for base and gain where base = 1024 and gain = 200 # Kamtal's method in considering base and gain RawUnits=3, rawUnits=4 use then again analog/digital units where you need to remove base and gain. RawUnits=1, rawUnits=2 use also physical units.
![matlab 64-bit double precision matlab 64-bit double precision](https://2.bp.blogspot.com/-iKkNNTBwb2Y/VxDV32O5vvI/AAAAAAAALj0/X71CiVOsVcEBEsSf_Lzto8yR5f6Taa7cwCLcB/s1600/121.png)
#Matlab 64 bit double precision 64 Bit#
% rawUnits=4 -returns both tm and signal as 64 bit integers (long). % rawUnits=3 -returns both tm and signal as 16 bit integers (short).
#Matlab 64 bit double precision 32 bit#
% rawUnits=2 -returns tm ( millisecond precision only! ) and signal in physical units with 32 bit (single) floating point precision % rawUnits=1 -returns tm ( millisecond precision only! ) and signal in physical units with 64 bit (double) floating point precision % rawUnits=0 - Uses Java Native Interface to directly fetch data, returning signal in physical units with double precision. The default units are now physical units where base and gain should be added stated in the header for each channel, so the physical signal can be mapped out for processing. Each 16 bit block stores an integer value between -2^15 and 2^15-1, and using the gain and offset stated in the header for each channel, the original physical signal can be mapped out for processing. This includes our precious 64 bit double precision floating point values, but this is as close as we can get and already very close to the actual physical values, so we refer to them as 'physical'.įor example, if a 15 bit signal is collected via a capturing device, Physionet will likely store it as a 16 bit signal. We say that signals are in 'physical units' when the values are used to represent the actual real life values as closely as possible, although obviously everything on the computer is digital and discrete rather than analogue and continuous.
![matlab 64-bit double precision matlab 64-bit double precision](https://3.bp.blogspot.com/-PdWVO9i5QSg/WRPTkhKfDtI/AAAAAAAAAg8/_i1zBSKB5LwAGy-3ZQKG1eXBGkPz79-xACLcB/w1200-h630-p-k-no-nu/MATLAB.png)
Once again you can quickly compare the values to see if they are in the expected physiological range of the signal you are analyzing. If they are not integers then they are physical. For example, if the header states that the signal is an ECG stored in milivolts, which typically has an amplitude of about 2mV, a signal of integers ranging from -32000 to 32000 probably isn't giving you the physical ECG in milivolts. Compare the values to see if they are in the expected physiological range of the signal you are analyzing. If they are all integers in the range or, they are probably digital. info file in some cases, you need to click the arrowĪfter I pushed this forward to developers here, we got improvements in the documentation here in Section 4. mat as described by Kamtal (now known Rashid).