9
Test Point J
IF Receive Signal:
The intermediate frequency (IF) receive signal is the down-
converted receive signal prior to the SAW bandpass filter.
The center frequency of this signal is 374MHz with a
bandwidth of 17MHz. The power of this signal is directly
dependent on the input signal power.
Note that the spurious signal visible below the DS
spectrum’s frequency is a harmonic of the 44MHz clock.
Much of this level is due to stray pickup in the 500
Ω
RF
probe because of the relatively low signal level present. As
such, it will have no influence on receiver performance.
Test Point K-K1 and L-L1
Receive I and Q:
NOTE: BPSK mode is used for the plots in this figure; as such, I and
Q are inverse of each other.
The receive In-phase and Quadrature (I and Q) signals are
the demodulated lowpass-filtered data that are coupled to
the HFA3861. The output levels of these two signals are
approximately 500mV
P-P
. As these are balanced signals,
data is taken using a Tektronix P6247 Differential Probe.
• Test point K for RXI+ signal is at the 0
Ω
jumper, R19.
• Test point K1 for RXI- signal is at the 0
Ω
jumper, R23
• Test point L for RXQ+ signal is at the 0
Ω
jumper, R27
• Test point L1 for RXQ- signal is at the 0
Ω
jumper, R29.
FIGURE 10. IF RECEIVE SIGNAL PRIOR TO SAW FILTER
(TEST POINT J)
FIGURE 11. RECEIVE I AND Q SIGNALS (TEST POINTS K AND L)
PIN 1
PIN 35
PIN 34
PIN 68
TOP (LED, THIS SIDE)
BOTTOM
VIEW, LOOKING INTO 68 PIN FEMALE CONNECTOR
3V KEY
FIGURE 12. EDGE VIEW, PCMCIA CARD
Application Note 9864
