User guide

sequential key presses). Once compressed, data can be rewound and fast-forwarded as

described in the previous section. The data can be expanded back after being compressed

by pressing and holding the MENU key and then pressing the EXPAND (◄) button.

Note that compression displays peak values (both high and low). Thus even though data is

compressed, all amplitude information is present on the display. At compressions of 16

times or greater, the redraw time of data on the screen slows down due to the large

amounts of data that must be manipulated.

 At any stage during the compression or expansion process, the screen can be

restored to current or real time display by pressing the MENU button.

 When the data on screen is compressed, a  appears on the status line to

indicate that the compress mode is active.

3.4 ZOOMING DATA (AMPLIFICATION)

As a result of the small display area available, it is not always possible to see small

changes in amplitude of the recorded signals even though the resolution of the internal

converters can measure it. To overcome this problem you can ZOOM in on a portion of the

graph and get increased resolution.

ZOOM applies to each channel independently. The trace that will zoom is the one whose

scale is shown to the right. To adjust the other trace, simply wait for its scale to appear.

To ZOOM in and amplify the graph, press and hold the MENU key, press the ZOOM+ (▲)

button and then release both buttons. The display will zoom in by 2. Note that the scale units

change to reflect the increased zoom level. There are three zoom levels available: x1, x2 and x4.

To decrease the zoom level (or zoom out), press and hold the MENU key, press the

ZOOM- (▼) button and then release both buttons.

While adjusting the zoom, scale flipping is suspended. Turning the other trace off will also

suspend flipping.

Note that when zoomed in at any zoom level, the (▲) and (▼) buttons will move the graph

relative to the window enabling viewing of any part of the graph within the zoom window.

When zooming, the trace expands or contracts about the centerline. If zooming drives the

trace off the screen, it will automatically reposition itself at the top or bottom vertical edge of

the chart. Once in a zoom level, all functions are operational on the zoomed display.

 When in a zoom mode, the zoom level is indicated in the lower half of the scale for

the associated channel (X2, X4 etc.). No indication indicates normal scale (X1).

 To exit the zoom mode, zoom out (MENU + ▼) as far as possible until the scale

value disappears – x1 mode.

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