U3550BM Datasheet, PDF (4/25 Pages) TEMIC Semiconductors – Low-Power FM Transmitter / Synthesizer System 26 to 50 MHz

U3550BM
Frequency Synthesis
VCO 3
2 ^fLO
Loop
filter
3)
N
Phase
f_Ref3
comparator
96 11627
K
11.15 MHz
D1
D2
2)
f_Ref
VCO 2
Loop
filter
Phase
comparator
VCO 1
2
D3
f_mod
Loop
filter
P+ ^Q
223
1)
1) _{Modulator loop}
2) _{Mixer loop}
3) _{Local oscillator (LO) loop}
Phase
comparator
f_Ref1 =
557.5 kHz
Figure 3.
Modulator Loop and Mixer Loop Dividers
France
D1
D2
D3
f_Ref2 (MHz)
f_mod (MHz)
4
8
2
1.075
4.3
Spain
2
8
4
0.9
1.8
Netherlands
2
8
4
0.9
1.8
Portugal
2
8
4
0.625
1.25
USA (channels 1 to 10)
8
8
1
0.955
7.64
USA (new channels)
6
6
1
0.943
5.66
Taiwan
8
8
1
0.9625
7.70
New Zealand
4
8
2
0.5875
4.70
Korea
8
8
1
0.955
7.64
For France, Spain, Netherlands, Portugal, Taiwan and New Zealand, f_Ref2 and f_mod do not change when the channel changes. For USA
and Korea is valid: f_Ref2 and f_mod are varying according to the channel number. For all countries, f_Ref2 and f_mod are identical for base
set and handset.
Reference Frequency Dividers for Local Oscillator
K₀ = 4460
K₁ = 2230
K₂ = 1784
K₃ = 1115
K₄ = 892
K₅ = 446
f_Ref3 = 2.5 kHz
f_Ref3 = 5 kHz
f_Ref3 = 6.25 kHz
f_Ref3 = 10 kHz
f_Ref3 = 12.5 kHz
f_Ref3 = 25 kHz
4 (25)
Rev. A2, 10-Sep-98
Preliminary Information