MULTI BURST TEST CHART (1 - 6 MHz)

REFLECTANCE

The test chart is designed for resolution measurements, mainly for visual test.

The chart consists of 4 rows with each 6 fields of multiburst of frequencies from 1 to 6 MHz.

The order of fields is switched in every second row. Only a limited depth of modulation

measurement is possible because there is no 0.5 MHz reference on the chart. You can

use the 1 MHz as a reference but be aware, that the results are not comparable with

usual measurements with e.g. T03, T07, TE99 and TE107. But there are more fields with

different frequencies available as e.g. in T03 and TE176 and the different frequencies

are better distributed over the picture area compared to e.g. the T07, TE99 and TE107.

Measuring equipement: video oscilloscope, preferably with memory function

Measuring conditions: The camara setting must be as follows

Shading correction: ON

Aperture correction: OFF

Gamma correction: OFF

Contour correction: OFF

Color 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 frequency burst at 1 MHz the amplitude

of the video signal at the output of the correctly positioned and focussed camera is 0% (0V)

for the black bars and 100% (700mV / 75 Ohms) for the white bars.

Care must be taken to avoid clipping of the signal to be measured at the black and white level.

Measurement procedures

Measurements can be made on the various camera output signals, but preferably on the

Y luminance signal (or coded Y with perfect B and W balance). The measurement is made

at the center of the image and at the corners so that account is taken of the lateral chromatic

aberation of the lens. In addition to determining camera response to the particular value of 5

MHz, measurement according to the spatial frequency of the test chart. Frequency bursts of

1 MHz and 2 to 6 MHz are recommended for this measurement. The measurements give the

contrast loss of the camera response at the value of 2 to 6 MHz. The obtained response is

a contrast transfer function (CTF).

Mathematical relations can be used to calculate the MTF according to the CTF values:

MTF(N)= π/4[CTF(N) + 1/3 CTF(3N) - 1/5 CTF(5N) + 1/7 CTF(7N) - 1/9 CTF(9N) + 1/11 CTF(11N) ...]

where N is spatial frequency of the test chart analysed; N in TVL/H