SN761685_14 Datasheet, PDF (9/14 Pages) Texas Instruments – TV TUNER IC

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Test Circuits
SN761685
TV TUNER IC
SLES175 – APRIL 2006
SG
50 Ω
50
2.2 nF
DUT
VLO IN
IFOUT1
IFOUT2
V_IN
2.2 nF
Vout diff
2.2 nF _{50 Ω}
V_OUT
Spectrum
Analyzer
50 Ω
GC = 20log(Vout diff / V_IN) = 20log(V_OUT / V_IN) + 6
Figure 12. VHF-L Conversion Gain-Measurement Circuit
SG
50 Ω
V
V_IN
2.2 nF
DUT
2.2 nF
VHI IN1
(UHF IN1)
IFOUT1
50 Ω ^{2.2 nF}
VHI IN2
(UHF IN2)
IFOUT2
2.2 nF _{50 Ω}
Spectrum
Analyzer
V_OUT
50 Ω
GC = 20log(Vout / V_IN)
Input: No Matching
Figure 13. VHF-H, UHF-Conversion Gain-Measurement Circuit
Noise
Source
2.2 nF
DUT
2.2 nF
VLO IN
IFOUT1
IFOUT2
2.2 nF _{50 Ω}
NF Meter
Figure 14. VHF-L Noise-Figure Measurement Circuit
Noise
Source
2.2 nF
DUT
2.2 nF
VHI IN1
(UHF IN1)
IFOUT1
2.2 nF
VHI IN2
(UHF IN2)
IFOUT2
2.2 nF _{50 Ω}
NF Meter
Figure 15. VHF-H, UHF Noise-Figure Measurement Circuit
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