Texas Instruments TRF3701, Руководство пользователя, Страница: 12 / 29

TRF3701/02 EVM Operating Procedure
1-4
c) Switch on the
±
7-V op amp supply, then turn on the precision
regulated power supply connected to J13, set to VCM, and used to
provide the VCOM1 and VCOM2 voltages (if needed).
3) Use a suitable 50-
Ω
output signal generator to supply the LO signal:
0 dBm.
4) Use an arbitrary waveform generator to provide the I/Q input signals. A
typical setup is as follows: a 1-Vp-p sine wave, a frequency of 900 KHz,
a dc-offset of 0 V, and an output impedance 50-
Ω
.
5) Connect a spectrum analyzer to the SMA connector marked RFOUT (J3)
and monitor the TRF3701/TRF3702 output.
6) To optimize the carrier suppression, this modulator performs the following
(if using on-board dc offset through J3):
a) Connect a spectrum analyzer to output port J3, rotate R33 to decrease
the LO feed through as required.
b) Then rotate R34 to further decrease the LO feed through.
c) Repeat this procedure until you obtain the minimum LO feed through.
A typical optimized sideband suppression value is 60 dBc.
7) Use an arbitrary waveform generator to suppress the sideband. Adjust the
I/Q amplitude and phase of the CW signal coming from the arbitrary
waveform generator. A typical optimized side band suppression value is
60 dBc.