AD1954–Typical Performance Characteristics
0
–2
The following plots demonstrate the performance achieved on the
actual silicon.TPC 1 shows an FFT of a full-scale 1 kHz signal,
with aTHD+N of –100 dB, which is dominated by a second
harmonic.TPC 2 shows an FFT of a –60 dB sine wave, demon-
strating the lack of low-level artifacts.TPC 3 shows a frequency
response plot with the seven equalization biquads set to an alter-
nating pattern of 6 dB boosts and cuts.TPC 4 shows a linearity
plot, where the measurement was taken with the same equalization
curve used to makeTPC 3.When the biquad filters are not in use,
the signal passes through the filters with no quantization effects.
TPC 4 therefore demonstrates that using double-precision math
in the biquad filters has virtually eliminated any quantization
artifacts.TPC 5 shows a tone-burst applied to the compressor,
with the attack and recovery characteristics plainly visible.The
rms detector was programmed for normal rms time constants;
the hold/decay feature was not used for this plot.
–4
–6
–8
–10
–12
–14
–16
–18
–20
20
50
100
200
500
1k
2k
5k
10k
Hz
TPC 3. Frequency Response of EQ Biquad Filters
0
–20
3.0
2.5
2.0
1.5
–40
1.0
–60
0.5
–80
0
–0.5
–1.0
–1.5
–2.0
–2.5
–3.0
–100
–120
–140
–160
0
2
4
6
8
10
12
14
16
18
20
–120
–100
–80
–60
–40
–20
0
kHz
dBFS
TPC 1. FFT of Full-Scale Sine Wave (32k Points)
TPC 4. Linearity Plot
0
–20
2.0
1.5
1.0
0.5
0
–40
–60
–80
–100
–120
–140
–160
–0.5
–1.0
–1.5
–2.0
0
2
4
6
8
10
12
14
16
18
20
–120
–100
–80
–60
–20
0
kHz
ms
TPC 5. Tone-Burst Response with Compressor
Threshold Set to –20 dB
TPC 2. FFT of –60 dB Sine Wave (32k Points)
REV. A
ADI [ ADI ]
