Texas Instruments TRF370 Series, Руководство пользователя

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1.4 TRF370x EVM Operating Procedure
Set up the EVM as follows:
1. Power-supply connection:
(a) Switch on the V
CC
(5-V) supply and set the current limit to 235 mA.
(b) Connect the 5-V supply to headers TP2 and TP4. Connect ground to TP1 and TP3.
(c) Verify that the current draw is
≤ 205 mA for the TRF370x1x and ≤ 235 mA for the TRF370333.
2. Use a suitable 50- Ω output signal generator or the TRF3761 to supply the LO signal at the desired
frequency to J1, and terminate J2 with 50 Ω to ground.
3. Use a DAC or 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 50 kHz, a dc offset of 0 V, and an output impedance of
50
Ω (typically an ESG vector signal generator or similar).
4. Set the common mode on the ESG to either 1.65 V, 0.75 V, or 0.85 V, depending on device type (set
to 1.65 V for the TRF370333, to 0.75 V for the TRF370315, or to 0.85 V for the TRF370x17).
5. 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.
6. Connect a spectrum analyzer to the SMA connector marked RFOUT (J7) and monitor the TRF370x
output.
1.4.1 Typical Test Results
1.4.1.1 Unadjusted Sideband Suppression
Unadjusted sideband suppression measures the amount of the unwanted sideband of the input signal,
relative to the wanted sideband. This assumes that the baseband inputs delivered to the modulator input
pins are perfectly matched in amplitude and are exactly 90° out of phase. Unadjusted sideband
suppression is measured in dBc. An iterative test is required in order to match perfectly the inputs to the
modulator. This ensures that any equipment, board, or signal conditioning component imbalances are
corrected before the signals are applied to the device under test. Once the baseband inputs to the
modulator are balanced, the amount of suppression attained is a measure of the internal mismatches of
the modulator, inherent to any modulator design. This suppression is the one specified in the TRF370x
data sheet. See
Figure 1 .
6 TRF370x Quadrature Modulator Evaluation Module SLWU062 – March 2010
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