MMSSTV  Ver 1.02 - What's New


--------------------------------------------------------------------------------

What's new on MMSSTV Ver1.02
June 18, 2001

JE3HHT Makoto Mori
Translated into English by JA7UDE Oba

***********************************************************************
Revision history: Ver1.01 -> Ver1.02
***********************************************************************
- Added the Hilbert transform method in the FM decoder
- Improved the processing speed of the low-level sound processing
- Added the TX-offset button on the Sync window
- Added High-accuracy slant adjustment method
- Added Vari-SSTV function
- Debugged the automatic start function
- Corrected some bugs and enhanced some functions


==================================
Added Hilbert transform method in the FM decoder
==================================
The figure below shows the flow of the Hilbert transform decoder. This idea was given by JA6UHL Nishimura-san (MNI TNX to JA6UHL).

--+-> Delay(N) -> Real
| |==> ATAN --> Differentiator --> LPF --> Pic. data
--> FIR(2N) --> Image


========================
Low-level sound buffer
========================
I enhanced the sound buffer processing. You can set the FIFO sizes for TX and RX in the option menu. 
If you often loose the sound, that is, loose the synchronization, try enlarging the RX FIFO or TX FIFO. Giving higher priority to the sound processing is another way of alleviate the sound loosing.


==============
High-accuracy slant adjustment
==============
MMSSTV uses the least square method to solve the linear equation for analyzing the synchronization timings. For high quality RX signals, it will give the error less than 2ppm.
To start the high-accuracy slant adjustment, push the NikoNiko button (comment by JA7UDE: the smiley button). You also can start it by right clicking on the sync or RX window and selecting High-accuracy slant adjustment in the pop-up menu. It should be noted that you must have received at least 16 scan lines to make this adjustment operational. The more the scan lines, the better the accuracy.


===============
Adjustment of TX offset
===============
Assuming that you have the RX clock calibrated, MMSSTV transmits the signal and receives it through the external loop back.
After you have adjusted the slant (push the NikoNiko smiley button), push the TX button in the Sync window. MMSSTV automatically records the TX offset frequency.


========
VariSSTV
========
VariSSTV, which is proposed by Mr. Samuel Hunt, is a method to protect the final device of the TX. He says that different colors have different brightness and therefore making the power lower in the way shown below gives better noise immunity.

Sync signal    100%
Red        29.8%
Green        58.8%
Blue        11%

For details, visit http://www.supersam.co.uk/sstvpwer.htm.

I have no idea how it is effective. Please give it a try by yourself. Go Option, Setup MMSSTV, TX tab, and check the VariSSTV box under the digital output level slider. This is not operational in Robot36 or Robot72.


***********************************************************************
Revision history Ver1.00 -> Ver1.01
***********************************************************************
- Added several SSTV modes
- Improved the image clipper function
- Added the preview tool for selecting files
- Fixed some bugs and improved some operations 


================
New SSTV modes
================

The following SSTV modes have been added.

    Name        Time(s)     Size             Method
    ---------------------------------------------------
    SC2-120        122         320x256         RGB
    SC2-60        62         320x256         RGB
    PD50        50         320x256         Color discrimination
    PD90        90         320x256         Color discrimination
    PD120        126         640x496         Color discrimination
    PD160        161         512x400         Color discrimination
    PD180        187         640x496         Color discrimination
    PD240        248         640x496         Color discrimination
    PD290        289         800x616         Color discrimination
    P3        203         640x496         RGB
    P5        305         640x496         RGB
    P7        406         640x496         RGB

To use one of these modes, click the mode button in TX or RX window with the right button of the mouse and select it from the pop-up menu.

PD120 - PD290 and P3 - P5 have bigger image sizes than 320 x 256 (from now on, I call them high-resolution modes). The image view board of the MMSSTV main window is designed to show a 320x256 image. For this reason, MMSSTV shrinks and displays the images (resized to 320x256) in those high-resolution modes. In other words, the sizes of the actual image and that displayed in the RX window would not be the same.

To view the high-resolution images in the original size, push the magnifier button under the RX or History window, or at the Always Show RX viewer, right click and select Resize to RX size in the pop up menu.

To view the high-resolution TX images in the original size, push the magnifier button under the TX window.

If the sizes in the TX mode and in the original image are different, MMSSTV does not resize the original image. If you want to resize the image, right click the TX window and select 'Stretch TX image by different size' in the pop-up menu. In this case, however, the image resolution sometimes degrades, particularly when you get it bigger. In addition, bear in mind that different modes have different aspect ratios.

Anyhow, it is recommended that you reload the image into the TX window if you use images in different sizes.

MMSSTV templates, therefore, have several sizes. It is a good idea to use the template whose size is the same as the image. In default, MMSSTV tries to get the template size to fit the image. However, the layout of the template components is not reserved.

You can resize the template size by selecting Size entry in the pop-up menu, which appears by right clicking the Template window. If the size of the template is different from that of the image, MMSSTV resizes the template and gets it superimposed to the image. It should be noted that the quality of the template would get worse, but you can continue to use the templates that you designed in different sizes.

The image size in the Stocked pictures are predefined as 320x256. If you want to change it, right click the Stocked pictures area and select Size in the pop-up menu.

When you drag & drop an image from the TX window to the Stocked pictures window, MMSSTV uses the TX image size.

In PD290, P5, and P7 modes, the RAM, which is used for the automatic slant adjustment, cannot store the whole image data. The slant and phase adjustment can be applied only to some portion of the data. To avoid this problem, select FILE for the RX buffer.


========================
New functions in the image clipper
========================

The following new functions have been added.

- Copy and paste without changing the original image size
- Rotate the image in 90 degrees
- Adjust the image
- Copy to the clipboard
- Save an image to a file

To use these functions, right click the image clipper window. You will get the pop-up menu for the functions.

================
Preview in file selection
================

In the dialog box for loading an image file, you can preview the image by clicking the file name.
The preview window is appeared at the top left corner for the first time, but you can change the size and position as you like.

73, Mako


--------------------------------------------------------------------------------

[ Home ]



 

 
undefined 
 
 
undefined 
More... 
 
 
undefined 
[Close] 
 
 
undefined 
[Close] 
 
 
undefined 
 
