SINUSOIDAL MULTI BURST TEST CHART

                             TRANSPARENCY

The test chart is designed for measuring horizontal static resolution. It shows vertical bars,

the density variation of which gives a sinusoidal video response. This is preferred to a

rectangular function test pattern, because this is in fact likely to create harmonic

frequencies which can impair resolution measurement owing to know „moirés“

phenomena in CCD Camera. The bars create frequencies of 0.5, 1, 1.5, 2, 2.5,

3, 4, 5, 6MHz.

Measuring equipment: Video oscilloscope or preferably videooscilloscope

                                        with memory.

Shading correction: ON

Aperture correction: OFF

Gamma correction: OFF

Contour correction: OFF

Colour correction: OFF

Iris: F/5.6 for 2/3 '' CCD, F/4 for 1/2 '' CCD

The test chart is evenly illuminated so that for the low frequency burst at 0.5 MHz

the amplitude of the video signal at the output of the correctly positioned and

focussed camera is 0% (0V) for the black bars of the zebra-strip and 100%

(700 mV / 75 Ohms) for the white bars of the zebra-strip.

Care must be taken to avoid clipping of the signal to be measured at the black

and white level. Measurements can be made on the various camera output

signal, but preferably on the Y luminance signal (or coded Y with perfect B

and W balance). The measurement give the contrast loss of the camera

response at the value of 5 MHz, the measurement of the response at other

frequency of the test chart. Frequency burst of 0.5, 2, 3, 5, and 6 MHz are

recommended for this measurement. The obtained response is a modulation

transfer function (MTF)

In the - probable - case of a beat affecting camera response for a given spatial

frequency, and under certain conditions only, the measured signal reassembles

an amplitude-modulated carrier signal, as shown in the following figure:

The percentage of modulation is then defined by the relation:

% mod = M / X

The interference ripple at this frequency is given by:

p %= m / M

This results of the measurement may be presented in the form of a table representing

the various areas of the imaging measured.