Lindos LA100 - Miscellaneous Features

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generated with the same rms level as sine waves (ie less peak to peak amplitude). The

peak to peak amplitude of sawtooth and triangular waveforms is the same as that for

sinusoids at the same level setting (so the rms level is 1.7dB lower). SAW+ and SAW-

provide sawtooth waveforms with positive and negative going slopes.

DOUBLE provides a double tone with 1011Hz centre frequency and 70Hz separation for

difference frequency distortion measurement (see section 2.16). No other double tone

frequencies can be generated and the bar graph shows the frequency which will be

generated when another waveform is selected.

Fig. 2.23 Sawtooth Waveforms Fig. 2.24 Peak Hold

2.25 Miscellaneous Features Inhibit autoranging Continuity detection Range setting Level range setting

Pressing on the LA102 inhibits autoranging and sets a fixed range which can be

changed using the

range keys. Selecting a new function changes the range to the

range last used for the newly selected function, and this can be useful on test tapes, where

autoranging on verbal announcements can be troublesome. Default values (after memory

clear) are 0dB, -30, -30, -30, -60dB for Level through to W&F. Autoranging returns on

the next

or reset. Manual range setting

toggles a peak hold function on the LA102. The numerical display is held

briefly and a marker appears on the bar graph (fig. 2.24). This is always switched in

automatically on W&F.

Sometimes, on noisy or low frequency signals the rms bar graph can jump around making

it difficult to read. Level option 9 overcomes this problem by providing a slow average of

the rms rectifier which is much more stable (although slower at settling), even down to

10Hz. The averaging is performed in software using a first order digital filter.

The LA101 can generate 22.5kHz sine waves for pilot tone continuity detectors. The

frequency actually generated is 22.4905kHz and is selected by holding

and

pressing

. and keys can be used to go to adjacent frequencies (22321Hz

and 22727Hz), but

must be used to return to this special frequency. This

frequency can also be used in ! tone segment definitions (section 4.16) and from remote

mode (see section 9.11). Also provided is 19.003kHz on

for FM stereo pilot

2. Manual Operation