Technical data

8-11
Preset State and Memory Allocation
Memory Allocation
Memory Allocation
The analyzer is capable of saving complete instrument states for later retrieval. It can store these
instrument states into the internal memory, to the internal disk, or to an external disk. This section
contains information on the following subjects:
• “Types of Memory and Data Storage” (below)
• “Determining Memory Requirements” on page 8-12
• “Storing Data to Disk” on page 8-14
• “Conserving Memory” on page 8-16
• “Using Saved Calibration Sets” on page 8-16
Types of Memory and Data Storage
The analyzer utilizes two types of internal memory and can also utilize the internal disk drive or be
connected to an external disk drive:
Volatile Memory
This is dynamic read/write memory, of approximately 4 Mbytes, that contains all of the parameters that
make up the current instrument state. An instrument state consists of all the stimulus and response
parameters that set up the analyzer to make a specific measurement. Some data that you may think is part
of the instrument state (such as calibration data and memory traces) are actually stored in non-volatile
memory. See “Non-Volatile Memory” to read more about the differences. Volatile memory is cleared upon a
power cycle of the instrument and, except as noted, upon instrument preset.
Non-Volatile Memory
This is CMOS read/write memory that is protected by a battery to provide storage of data when line power
to the instrument is turned off. With this battery protection, data can be retained in memory for
≈ 250 days
at 70
°C and for ≈ 10 years at 25 °C (characteristically). Non-volatile memory consists of a block of
user-allocated memory and a block of fixed memory. The user-allocated memory is available for you to save
the following data:
• instrument states
• measurement calibration data
• power meter calibration data
• user calibration kit definitions
• memory traces
• user preset
NOTE Even though calibration data is stored in non-volatile memory, if the associated instrument
state is not saved, you will not be able to retrieve the calibration data after a power cycle.
The fixed memory is used to store the following data (you cannot change where this data is stored and it
does not affect your memory availability for storing user-allocated data):
• GPIB addresses
• copy configuration (printer and plotter type, port, baud rate, handshake)
• power meter type (436/437/438)
• display colors