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| EVB71120_15 Datasheet, PDF (7/18 Pages) Melexis Microelectronic Systems – 300 to 930MHz Receiver Evaluation Board Description | |||
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EVB71120
300 to 930MHz Receiver
Evaluation Board Description
2.1 Calculation of Frequency Settings
The receiver has two predefined receive frequency plans which can be selected by the RFSEL control pin.
Depending on the logic level of RFSEL pin the sideband selection of the second mixer and the counter
settings for N1 and N2 are changed accordingly. (see in 1.5)
RFSEL
Injection
fRFmin [MHz]
fRFmax [MHz]
N1
N2
0
high-low
300
470
4
6
1
low-high
610
930
2
12
The following table shows the relationships of several internal receiver frequencies for the two input
frequency ranges.
fRF [MHz]
300 to 470
fIF1
f RF ï« N1f IF2
N1 ï1
fLO1
N1 (f RF ï« f IF2 )
N1 ï1
fLO2
f RF ï« f IF2
N1 ï1
fRO
f RF ï« f IF2
N2 (N1 ï1)
610 to 930
f RF ï N1f IF2
N1 ï«1
N1 (f RF ï« f IF2 )
N1 ï«1
f RF ï« f IF2
N1 ï«1
f RF ï« f IF2
N2 (N1 ï« 1)
Given IF2 is selectable at either 455kHz or 10.7MHz and the corresponding N1, N2 counter settings, above
equations can be transferred into the following table.
IF2=455kHz
fRF [MHz]
300 to 470
610 to 930
fIF1
fRF ï« 1.82M Hz
3
fRF ï 0.91M Hz
3
fLO1
4(fRF ï« 0.455MHz)
3
2(fRF ï« 0.455MHz)
3
fLO2
fRF ï« 0.455M Hz
3
fRO
fRF ï« 0.455M Hz
18
fRF ï« 0.455M Hz
36
IF2=10.7MHz
fRF [MHz]
300 to 470
610 to 930
fIF1
fRF ï« 42.8M Hz
3
fRF ï 21.4M Hz
3
fLO1
4(fRF ï«10.7MHz)
3
2(fRF ï« 10.7MHz)
3
fLO2
fRF ï« 10.7M Hz
3
fRO
fRF ï« 10.7M Hz
18
fRF ï« 10.7M Hz
36
39012 71120 01
Rev. 006
Page 7 of 18
EVB Description
Nov/15
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