D, Q, Ang In Ppm - IET Labs, Inc. RLC Digibridge 1693 User And Service Manual

1693 RLC Digibridge
Decimal Point Position. The decimal point is auto-
matically positioned for maximum resolution (i.e., so
that the first significant digit or the first zero after the
decimal point is in the first position in the display)
with a few exceptions, as listed below. Of course,
displays on low underrange or low extension of a held
range may have a number of necessary zeros to right
of the decimal point (and therefore reduced number
of significant digits compared to the display area)
because units and multipliers are fixed on anyone
range. The above-mentioned exceptions are:
• DQ IN PPM is always displayed without a
decimal point, in ppm.
• Delta% displays can resolve no less than
0.0001% (i.e., 1 ppm).
• Hysteresis is provided to reduce flickering, as
explained below.
If the first digit of the measurement is 9, the decimal
point for any measured-value display is left un-
changed from its previous position, provided that so
doing places that 9 in either the first or second position
in the display area. (Notice that a number like 09XXX
has resolution almost as fine as a number like 10xxx.)
For example, if the measured value is 99.985 nF, the
display is a full 5 digits if the previous measured-
value display was 12.345, 99.984, or 99.999; but the
display is rounded off to 099.98 nF if the previous
measured-value display was 100.02 or 1234.5 nF.
Hysteresis is provided on both measured-value dis-
plays (RLC and QDR).
40
Table 3-6: Units and Multipliers for Each Range
Blanks in Measured-Value Displays. If a measure-
ment exceeds the capability of the display (99999 for
RLC display, 9999 for QDR), the display is blank.
If a measurement is less than 1 right-hand digit, the
display is all zeros. If any leading zero before the
decimal point must occupy a position in the display,
that zero is blanked out.

3.3.5 D, Q, ANG in PPM

The Digibridge can easily be programmed to display
the secondary test result - when it it either D, Q or
ANG - in parts per million. To choose this display,
[SHIFT][DQ in PPM]
press:
so that the PPM indicator is lit. To disable this op-
tion, repeat the same keystrokes so that the indicator
is NOT lit. Units of D and Q in PPM are dimension-
less and are expressed as a decimal ratio, with the
multiplier of 1,000,000 understood. To obtain D or
Q in percent, from the DQ in PPM display, place a
decimal point four places to the left of its "under-
stood" position at the right-hand end of the display
. For example, a "DQ in PPM" display of D = 120
ppm is equivalent to 0.012%.
Operation