Edit time sampling trace parameters.

Изменение параметров времени трассы.

Edit time sampling trace parameters.

EDITT PEP-клиент.

The program is intended for changing of a step of discrete sampling, and also for changing of start and final recording time. The step of a discrete sampling can be increased or reduced in eight, four or two times. The program is applicable both for time, and for depth sections. In the last case it is necessary to use meters instead of milliseconds.

For changing of a step of discrete sampling the complex spectrum of a trace is calculated. Then, in a case of reduction of a step of discrete sampling in N times (N = 8, 4, 2) the length of a spectrum is increased in N times, and the zeroes are added to the right. In case of increasing of a step of discrete sampling in N times (N = 8, 4, 2) the length of a spectrum is reduced in N times, up to the half-frequency of Nyquist rate of an initial trace. Thus the part of a spectrum between a quarter and half of Nyquist rate is multiplied on COS. Further comes the inverse Fourier transformation for transition in time area. Whole trace or its fragment are recorded in the output modification, according to the spacified input data.

The resulting time interval (for a depth section) can be arbitrary. The missing samples are filled with zeroes, and the unnecessary - are rejected. During transformation of step and interval the signal on a trace is not shifted.

Interaction with other programs

The program is PEP-client. Thus it is started from under the shell of the packet execution program pktexec, which gives tools for setting of the parameters, control of execution of the program and viewing the protocol of program operation.

If it is necessary to shift traces in time, one can use a program SHIFTR.

Description

Session

The setting of parameters and start of the program is performed from under the shell of the packet execution program pktexec. The standard session consists of the following steps:

Start-up of the program from the menu of a VSP packet.
Setting of the project, the data directory of which contains the initial modification (menu item File - > Project...).
Setting of a name of input modification (field Input modification).
Setting of parameters of operation of the program:
- Parameter of changing of a step of a discrete sampling (field Sampling rate change);
- Start and final time in output modification (field Time range output modification).
Setting of a name of output modification (field Output modification).
Start-up of the program on execution (button Start in the toolbar or menu item EDITT - > Start).
On "scroll box" (Count of processed input traces) the relative number of processed traces is shown.
During execution of the program the cable depth of a trace, processed in the current moment, (field Trace cable depth) is shown also.
For viewing the protocol of the program execurion it is necessary to press the button View log in the toolbar or to select the menu item EDITT - > View log.
To escape the packet execution program it is necessary to press the button Exit in the toolbar or to select the menu item File - > Exit.

Parameters of processing

Input parameters (panel Parameters)

Input modification: Name: inmod
Type: nmod_s
Description: input modification
Sampling rate change: Name: param
Type: enum (* 8 |* 4 |* 2|the same |/ 2 |/ 4 |/ 8)
Description: this parameter specifies how and in how many times a step of discrete sampling will be changed. The step of discrete sampling can be increased or reduced in 8, 4, 2 times or to remain the same (mode "the same")
Time range output modification (ms): Name: trange
Type: float2
Description: time interval of a trace recorded in the output modification. The initial time of this interval should be not less than the start time of an initial trace, and the final time should be not more than the final time of an initial trace
Output modification: Name: outmod
Type: nmod_e
Description: output modification

Information on the operating time of the program (panel Runtime)

Count of processed input traces: Name: runner
Type: progress
Description: Shows a share of the processed input traces
Trace cable depth: Name: hcab
Type: float
Description: current cable depth

Parameters of results (panel Results)

Output modification: Name: outmod
Type: nmod_e
Description: output modification
Sampling rate in output modification (ms): Name: dtout
Type: float
Description: a step of discrete sampling in output modification

Time range output modification (ms)

Name: trangeout
Type: float2
Description: a resulting time interval in output modification.

User interface

For detailed acquaintance with the user interface of the shell of the package execution program, see the description of the program pktexec. An example of the window of the shell with active panel for input of parameters is given below:

Input data

Traces

The modification with traces, for which the user wishes to change a step of discrete sampling and/or start, final recording time, is moved to the input. The step of discrete sampling of initial traces must be those, that after its changing according to given the parameters, it fitted in an interval of 0.017 - 17 ms. All traces included in the input modification are processed.

The program can be used for operation both with depth and with time sections.

Output data

Traces

The output modification is formed by traces, in which step of discrete sampling, start and final recording time are modified according to the given parameters.

Requirements to the environment

Operational environment

The program gets the name of the current project through the variable of environment PROJECT. If the program is started from under the shell, this condition is fulfilled by selection of the operative project.

The program determines the location of the system files of the package from a variable VSPHOME, defined in the user`s profile or in the file setup in a home directory of the user of the package. In the file setup the given variable can appear also under the name of VSP.

Used files

The program searches for description of parameters in files $VSPHOME/etc/EDITT.pep and $VSPHOME/etc/vsp.pep.

At a home directory of the user there should be a file setup, containing paths to the directories of data, tasks and protocols of exexution of the project, and also paths to the system files of the VSP packet.

Other requirements

The other requirements are superimposed by the packet execution program pktexec.

Messages to the user

Bringing messages to the notice of the user

All messages are moved to the standard stream of errors. If the program is started from under the interactive shell, the messages are saved to the file of the protocol of the transmission of the job LOG/$PROJECT/EDITT-#.log. The messages of classes EL_FATAL and EL_ERROR are placed in the area of messages of the interactive shell after the program termination.

Description of the diagnostic messages

The following diagnostic messages are output in the information string:

WARNING: Negative time - use source range Tb.. Te ms: The user has specified the negative value for one of times of a resulting time range. This message tells, that the program has selected the initial range as the resulting range.
ERROR: Resulting sampling rate is out of range 0.017.. 17 ms: At attempt to reduce or to increase the step of discrete sampling the resulting value overstep a valid range.
ERROR: Error in time range.: Error message in setting of the stary or final time of the trace in the output modification. The start time should be less than final.
ERROR: Can't increase sampling rate due to Tb=N: The start time in the input modification should be divisible by the step of discrete sampling.
ERROR: Can not open ' %s modification due to ERROR __ some_error.: Error at opening of the input modification.
ERROR: Can not create ' %s modification due to ERROR __ some_error.: Error in creation of output modification.
" Can't allocate memory working buffer. ": Not enough memory contention for allocation of the working arrays. Probably the internal error of the program or error in the input data.

Изменение параметров времени трассы.