CCIF and DFD IMD Waveforms
Center Frequency Range 3.00 kHz to (47% of Sample Rate –½ IM freq.).
IM Frequency Range 80 Hz–2.00 kHz.
Distortion/Spurious £0.000001% [–160 dB].
DIM IMD Waveform
Square/Sine Frequencies Determined by Sample Rate (see Note below).
Distortion/Spurious £0.000001% [–160 dB].
The DIM test signal consists of a square wave and a sine wave
mixed in a 4:1 amplitude ratio. Since digital square waves are
generated by alternately turning the output on and off for the
same number of sample periods, the frequencies achievable
are limited to even sub-multiples of the Sample Rate. Because
of this constraint, the square wave frequency is chosen first to
be as close to the “ideal” analog test frequency as possible.
The sine wave frequency is then chosen based upon the ideal
sine/square frequency ratio. The following table lists some
examples for the DIM and DIMB signals:
Noise
Types Pink, White, Burst, USASI.
Special Signals
Monotonicity Low level staircase waveform for D/A linearity
testing.
J-Test Produces a maximum amount of data-induced
jitter on low-bandwidth transmission links.
Polarity Two sinewaves phased for reinforcement with
normal polarity.
Walking Ones A single binary one value “walked” from LSB to
MSB.
Walking Zeros A single binary zero value “walked” from LSB to
MSB.
Constant Value
(Digital dc) 32-bit resolution when using triangular dither.
Chapter 6: Specifications Digital Signal Generator
78 Getting Started with Your 2700 Series Instrument
DIM: “ideal” square frequency = 3150, sine/square frequency ratio = 100/21
Sample Rate Square Wave Frequency Sine Wave Frequency
44100 3150 15000
48000 3000 14285.7
DIMB: “ideal” square frequency = 2960, sine/square frequency ratio = 175/37
44100 3150 14898.65
48000 3000 14189.19
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