Agilent Technologies E1439 manual DataTypePtr, ModePtr, PortPtr, ResolutionPtr

Models: E1439

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Agilent E1439 Programmer's Reference

 

Functions listed alphabetically

 

when dataType is set to AGE1439_REAL and there is a non-zero center frequency the data scale

 

value is doubled for consistent spectrum measurements

dataTypePtr

points to the current value of the dataType parameter.

mode

selects whether the Agilent E1439's data collection operates in block mode or continuous mode.

 

AGE1439_BLOCK selects block transfer mode in which the measurement is halted after each

 

block of data. To start collection of the next data block the module must be armed and triggered

 

again. This mode is used whenever each block of data is to be associated with an individual

 

trigger event.

 

AGE1439_CONTINUOUS means that a single arm and trigger event starts a measurement which

 

runs continuously with no gaps between output data blocks. The measurement continues as long

 

as the data is read out fast enough to prevent overflow in the output FIFO. The continuous mode is

 

useful for continuous signal processing applications where data gaps are unacceptable.

modePtr

points to the current value of the mode parameter.

port

determines which output port is used to take data from the Agilent E1439 module.

 

Setting port to AGE1439_VME means the data is to be output using standard VME register reads.

 

This is the instrument default.

 

Setting port to AGE1439_LBUS means the data is to be output as a byte-serial data stream via the

 

VXI local bus (Agilent E1439D only) . When using the local bus port the module immediately to

 

the right of the Agilent E1439 must be capable of receiving the local bus byte sequence.

 

Setting port to AGE1439_FIBER means the filtered ADC data is to be transmitted as a serial data

 

stream over the fiber interface.

portPtr

points to the current value of the port parameter.

resolution

selects data resolution of either 12 or 24 bits by using resolution values of AGE1439_12BIT or

 

AGE1439_24BIT respectively. Choosing 12-bit precision allows for more samples in the FIFO

 

memory. Choosing 24 bits allows more dynamic range. Because of the broadband white noise

 

present on the input of the analog-to-digital converter, it is normally sufficient to use 12 bit

 

resolution whenever the age1439_filter_setup function specifies a signal bandwidth greater than

 

10 MHz. For narrower bandwidths much of the broadband white noise is filtered out, resulting in

 

lower noise in the output data. To take advantage of this lower noise, you should use the 24-bit

 

data resolution.

resolutionPtr

points to the current value of the resolution parameter.

 

Comments

 

The following table summarizes the output word or byte sequence for each combination of

 

dataType, resolution, and port parameters:

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Page 102
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Agilent Technologies E1439 manual DataTypePtr, ModePtr, PortPtr, ResolutionPtr