CMX991 Datasheet, PDF (31/56 Pages) CML Microcircuits – Two-mode demodulator

RF Quadrature Transceiver / RF Quadrature Receiver
CMX991/CMX992
6.6
6.6.1
Tx Mode Register (CMX991 only)
Tx Mode Register:
8-bit write-only
C-BUS address $15
This register controls transmitter features.
All bits of this register are cleared to ‘0’ by a General Reset command.
Bit:
7
0
6
5
4
3
0
IF_Filter
IF_Filter
0
BW2
BW1
2
HiLo
1
TxRFDiv
0
TxIFDiv
Tx Mode Register b7 and b6
Reserved set to ‘0’.
Tx Mode Register b5 and b4
These bits select the Tx IF filter bandwidth:
b5
b4 Tx IF filter bandwidth
0
0 45MHz
0
1 60MHz
1
0 90MHz
1
1 120MHz
For further information see section 7.12.
Tx Mode Register b3
Reserved set to ‘0’.
Tx Mode Register b2
This bit controls the mixing arrangements in the image-reject up-converter as follows:
b2 = ’0’
b2 = ‘1’
f_rf = f_lo - f_if
f_rf = f_lo + f_if
Tx Mode Register b1
Controls the divider for the RF Local Oscillator: b1 = ’0’ selects RF LO divided by 2 mode and
b1 = ’1’ selects RF LO divided by 4 mode.
Tx Mode Register b0
Controls the divider for the IF Local Oscillator: b0 = ’0’ selects IF LO divided by 4 mode and
b0 = ’1’ selects IF LO divided by 2 mode.
6.6.2 Tx Mode Register
8-bit read-only
C-BUS address $E5
This read-only register mirrors the value in register $15; see section 6.6.1 for details of bit functions.
6.7 Tx Gain Register (CMX991 only)
6.7.1 Tx Gain Register:
8-bit write-only
C-BUS address $16
This register controls transmitter gain features.
 2015 CML Microsystems Plc
31
D/991_992/20