LDI Intellectual Property.
Not for secondary distribution or replication, in part or entirety.
DIGISONDE-4D
SYSTEM MANUAL
VERSION 1.2.11
SECTION 5 - SYSTEM SOFTWARE – ANNEX A 5-31
5:85. Common Specifications define all parameters that are common to both ionogram and drift mode of
Digisonde
®
operations. This part includes, for example, frequency and range stepping, number of pulses per
frequency, signal waveform, etc. Common Specifications determine how the time domain data are collected by
the DESC and forwarded to DCART.
5:86. There is a variety of Data Processing that both DESC and DCART can apply to the collected time do-
main data in order to produce the final data product to be archived (i.e., an ionogram or a drift measurement).
Number and sequential order of the processing steps that are required to derive the final DCART data product
from the raw time domain data depend on:
• choice of data product (i.e., ionogram, drift record, or intermediate step data),
• choice of DPS signal waveform, and
• optional processing, such as the RF Interference Mitigation (RFIM).
5:87. The variety of processing steps and processors that execute them is described in terms of one linear
sequence of Data Process Steps, called Process Chain. The Process Chain has the following properties:
• Data Process Steps in the chain are applied successively to the raw time domain data
• The complete Process Chain has the following sequence of 5 process steps
0. Raw data (no processing applied)
1. Pulse Compression
2. Sum of complementary code sequences
3. Doppler Processing
4. Ionogram Calculation
• Process Chain can be made shorter to produce intermediate step data, but only by removing steps from
the end of the chain.
• Each step in the Process Chain can have any number of optional unchained process steps attached to its
output.
5:88. The main Process Chain can be described by one byte, the ID of the last data process step (0 to 4). Se-
lection of the unchained steps can be described by one byte, where each bit corresponds to the one of the avail-
able unchained steps. Currently two unchained steps are provided,
0x1. Channel Equalizing (CEQ), applied at the output of chained step 0
0x2. RFI Mitigation, applied at the output of chained step 0
5:89. Therefore, the following settings of the unchained step selection are possible:
0 = no unchained steps called,
1 = Channel EQ
2 = RFI Mitigation,
3 = both RFIM and Channel EQ.
To Next Page
Loading...