2-34
Modulator Architecture
The default offset value for all four phases is 0. To shift the shifter by
default, set it to 5 bits.
2.11.3 Default Filter Characteristics
Figure 2.20 shows the characteristics of the L64777 default filter.
Figure 2.21 Square-Root Raised Cosine Filter
2.12 Global Control and PLL Module
The L64777 interface supports serial and parallel input modes at the
input interface. The global control generates the clocking for the input
and output interfaces; it also controls the data path. It contains all the
necessary logic to chain the processing units together.
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
-8000
-6000
-4000
-2000
0
Normalized frequency (Nyquist == 1)
Phase (degrees)
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
-150
-100
-50
0
50
Normalized frequency (Nyquist == 1)
Magnitude Response (dB)
Magnitude Response (dB)
50
0
−
50
−
100
−
150
Phase (deg
rees)
0
−
2000
−
4000
−
6000
−
8000
0
0.9
1.0
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
Normalized Frequency (Nyquist = 1)
0
0.9
1.0
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
Normalized Frequency (Nyquist = 1)
Summary of Contents for L64777
Page 1: ...L64777 DVB QAM Modulator Order Number I14031 A Technical Manual June 2000...
Page 10: ...x Contents...
Page 14: ...1 4 Introduction...
Page 90: ...5 10 Signals...
Page 110: ...A 8 Programming the L64777 in Serial Host Interface Mode...
Page 116: ...C 2 Monitoring Device Internal Signals...
Page 124: ......
