Notes from the Web: The Yamaha CDX-1100 is the first player to achieve the performance of
18-bit digital decoding from a 16-bit digital-to-analog (d/a)
converter. In addition, it provides almost every operating convenience
currently available in a CD player.
The CDX-1100 uses 18-bit quadruple-oversampling digital filters
for each channel. The 176.4-kHz sampling rate of the filters greatly
reduces noise in and just above the audio range compared with
nonoversampling, 44.1-kHz filters. Since the spurious products and noise
created by the digital sampling process are far above the 20-kHz upper
frequency limit of the CD system, they can be removed by a digital
filter, in conjunction with a fifth-order active analog filter, that has a relatively gradual slope and a high cutoff frequency. These
characteristics help preserve a flat response and produce less phase
shift and ripple within the audio range. Compared with 44.1-kHz
sampling, quadruple oversampling gives a fourfold improvement in
time-axis resolution, although this is normally beneficial only at the
higher program levels. Yamaha's 18-bit filters extend this improvement
to the low-level portions of the program, where they also provide a
fourfold improvement in amplitude resolution and correspondingly lower
distortion.
The peak levels on a digital disc rarely reach the two highest,
or most significant, bits of a 16-bit system, so the full capability
even of 16-bit d/a conversion is needed relatively infrequently. Many CD
players, in fact, use 14-bit decoders without a significant loss of
quality. Nevertheless, distortion increases rapidly as the program level
decreases, and it is concentrated in the less significant bits of the
digitally encoded signal. In fact, a pure sine-wave signal represented
by the least significant bit is actually decoded into a square wave with
a very high percentage of harmonic distortion, although it is not
likely to be audible as such because of its very low level and masking
by the other program material.
Specifications
Disc format: CD
Digital converter: 2 x PCM56P-K, 18 bit
CD Mechanism: MLP-7
Frequency response: 1Hz to 20kHz
Dynamic range: 100dB
Signal to Noise Ratio: 115dB
Channel separation: 100dB
Total harmonic distortion: 0.002%
Line output: 2V
Digital outputs: optical
Dimensions: 435 x 121.5 x 416mm
Weight: 14kg
