U3550BM Datasheet, PDF (13/25 Pages) TEMIC Semiconductors – Low-Power FM Transmitter / Synthesizer System 26 to 50 MHz

U3550BM
Channel Frequencies, Dividers and Country Settings
* To meet all requirements of various countries France (F), Spain (E), Netherlands (NL), USA and Portugal (P), Korea,
* * * Taiwan, New Zealand and modes base (b), handset (h) several bits have to be set which do not change for
the different channels. These settings are called country settings.
The country-setting bits are followed by further bits enabling the adjustments given below.
D Rough adjustments for 2 VCOs
D Setting three integer dividers mixer and
modulator loop
D Gain adjustment of the VCO2
D Modulator gain
D Up-/down-mixing Mixer 1 and Mixer T
D Output-frequency range of Mixer T
Name Register
RA1[0:1]
RA2[0:1]
D1[0:1]
D20
D3[0:1]
KV[1:3]
GMOD[0:1]
IMIXI
UDM1
FRMT
Function
Notes
Rough adjust VCO1
00: is the highest frequency
3
Rough adjust VCO2
00: is the highest frequency
4
Integer divider D1
Division by 2, 4, 6, 8
4
Integer divider D2
Division by 6, 8
2
Integer divider D3
Division by 1, 2, 4
3
Gain VCO2
6
Modulator gain
00: gain minimal
3
Up-/down-mixing
Mixer T
0: if f_VCO2 lower than f_LO
2
Up-/down-mixing
Mixer 1
1: supra band active (handset)
2
Output-frequency range
0: for f_VCO2 – f_LO < 6 MHz
2
Mixer T
Note: Setting the fractional dividers:
For Q, send the binary equivalent of the numbers given below.
For P (integer part), send the D2 complement (16 – P)
i.e. Fb1 (P = 7, Q = 159 => integer: send 16 – P = 9, fractional: send 159)
Rev. A2, 10-Sep-98
Preliminary Information
13 (25)