CMX994 Datasheet, PDF (27/61 Pages) CML Microcircuits – Local Oscillator

Direct Conversion Receivers
CMX994/CMX994A/CMX994E
7.3
7.3.1
Rx Control Register
Rx Control: $12 – 8-bit write only
This register controls general features of the receiver such as Powersave. All bits of this register are cleared to
‘0 by a General Reset command.
7
6
5
4
3
2
1
0
Mix Pwr
IQ Pwr
LNA Pwr ACR Flt2 ACR Flt1 DC Range
DIV2
DIV1
b7-5 These bits control power up/power down of the various blocks of the IC.
In all cases ‘0’ = power up, ‘1’ = power down.
b7 Disable receiver mixers and divider (see
note)
b6 Disable baseband amplifier and filters
(see note)
b5 Disable LNA (see note)
Note: These control signals disable the appropriate blocks of the receiver when ‘Rx ON’ is active. If ‘Rx ON’ is
not active all receiver circuits will be in powersave mode.
b4,3 The baseband I/Q chain provides a narrow filter for rejecting adjacent channel signals. The
bandwidth of this filter may be scaled using these bits. For further details see sections 6.2.2, 6.2.3
and 8.1.6.
b4 b3
0
0
0
1
1
0
1
1
Function
Minimum bandwidth
Intermediate bandwidth
Maximum bandwidth
reserved, do not use
b2
When b2 = ’0’ the range of DC correction of the I/Q output is nominal (see sections 6.2.1 and 7.4).
With b2 = ‘1’ the total correction range is twice the nominal specified in section 7.4 with all steps
doubled in value. Note: CMX994A/CMX994E provide an alternative method of achieving increased
correction range without losing resolution using the Extended Rx Offset Register ($17); see section
7.8.
b1,0 Receiver LO divider control
b1 b0 Function
0
0 LO divided by 2
0
1 LO divided by 4
1
0 LO divided by 6
1
1 reserved, do not use
7.3.2 Rx Control: $E2 – 8-bit read only
This read-only register mirrors the value in register $12; see section 7.3.1 for details of bit functions.
 2015 CML Microsystems Plc
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