AD1954 Analog Devices, AD1954 Datasheet - Page 8

• Manufacturer Part Number: AD1954
• Description: SigmaDSP Digital Audio Processor
• Manufacturer: Analog Devices

AD1954–Typical Performance Characteristics
PERFORMANCE PLOTS
The following plots demonstrate the performance achieved on
the actual silicon. TPC 1 shows an FFT of a full-scale 1 kHz
signal, with a THD + N of –100 dB, which is dominated by a
second harmonic. TPC 2 shows an FFT of a –60 dB sine wave,
demonstrating the lack of low-level artifacts. TPC 3 shows a
frequency response plot with the seven equalization biquads set
to an alternating 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 make TPC 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.
–100
–120
–140
–160
–100
–120
–140
–160
–20
–40
–60
–80
–20
–40
–60
–80
+0
0
0
0
2
2
4
4
6
6
8
8
PRELIMINARY TECHNICAL DATA
kHz
kHz
10
10
12
12
14
14
16
16
18
18
20
20
–500m
500m
–0.5
–1.0
–1.5
–2.0
–2.5
–3.0
–1.0
–1.5
–2.0
–10
–12
–14
–16
–18
-20
3.0
2.5
2.0
1.5
1.0
0.5
2.0
1.5
1.0
–0
–2
–4
–6
–8
–120
0
–120
0
20
–100
–100
50
100
–80
–80
200
dBFS
–60
ms
Hz
500
–60
–40
1k
–20
–20
5k
10k
0
0