RF Quadrature Transceiver / RF Quadrature Receiver
CMX991/CMX992
Rx Control Register b2 and b1
RF LO Divider control.
b2 b1
0
0
1
1
0
1
0
1
RF MIXLO input divide by 2
RF MIXLO input no division
RF MIXLO input divide by 4
reserved – do not use
6.3.2 Rx Control Register C-BUS address $E2
8-bit read-only
This read-only register mirrors the value in register $12; see section 6.3.1 for details of bit functions.
6.4
Rx Mode Register (CMX991/CMX992)
6.4.1 Rx Mode Register:
8-bit write-only
C-BUS address $13
This register controls operational modes of the receiver such as gain setting.
All bits of this register are cleared to ‘0’ by a General Reset command.
7
6
5
4
3
2
1
0
Bit:
IFin
Mix Out
I/Q Filter
Cal En
VGA4
VGA 3
VGA 2
VGA 1
Rx Mode Register b7 and b6
Mixer and IF Amplifier signal routing. b7 selects the IF input, b7 = ‘0’ selects IFIP1 and b7 = ‘1’
selects IFIP2. b6 selects the IF output of the Rx 1st Mixer, b6 = ‘0’ selects MIXOUT1 and b6 = ‘1’
selects MIXOUT2.
b7 b6
0
0
1
1
0
1
0
1
Mixer output on MIXOUT1; IF input on IFIP1 and IFINN
Mixer output on MIXOUT2; IF input on IFIP1 and IFINN
Mixer output on MIXOUT1; IF input on IFIP2 and IFINN
Mixer output on MIXOUT2; IF input on IFIP2 and IFINN
Rx Mode Register b5
Writing b5 = ’1’ I/Q Filter BW = 1MHz; Writing b5 = ’0’ I/Q Filter BW = 100kHz.
Rx Mode Register b4
Enable Calibration Mode: disable LNA and 1st Mixer when b4 = ’1’; normal operation when b4 = ’0’.
For further details see section 5.2.4.
Rx Mode Register b3 - b0
VGA Control. For further details see section 7.3.2.
b3
b2
b1
b0
1
0
0
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
0
1
0
1
0
1
VGA= -48dB
VGA = -42dB
VGA = -36dB
VGA = -30dB
VGA = -24dB
VGA = -18dB
2012 CML Microsystems Plc
29
D/991_992/18
CMLMICRO [ CML MICROCIRCUITS ]
