240 Chapter
10
oscillators and PLLs which must not be neglected. Phase noise modeling and
simulation within transmission systems is an important task.
Table 10-7. Oscillator parameters
Parameter Value
Output frequency (Hz)
2.6G
Output power (dBm)
-30
Output impedance ( ) 50
Noise floor (dBc/Hz)
-150
Frequency point f1 (Hz)
2M
Phase noise at f1 (dBc/Hz)
-103
Corner frequency (Hz)
0
Phase shifter
Table 10-8 shows the properties of the phase shifter which combines a
shifter and a signal splitter. The operation frequency is set to 2.6 GHz.
Table 10-8. Phase shifter parameters
Parameter Value
Operating frequency (Hz)
2.6G
Internal resistance ( ) 100
10.4.2
Simulation of the WLAN receiver
Frequency conversion
The depiction of the frequency conversion inside the WLAN receiver can
be realized using SpectreRF [Cad03a] with a Periodic Steady State (PSS)
analysis. This large-signal analysis uses harmonics of a determined beat
frequency (also known as PSS fundamental frequency) to calculate the
output signal. In the PSS setup the beat frequency can be calculated
automatically according to the available sources and their frequencies. For a
better visualization of the results a beat frequency of 50 MHz is chosen.
Figure 10-17 shows the results of the PSS simulation calculating 180
harmonics. The RF signal lies at 5.2 GHz with a power amplitude of -
76.5 dBm. The LO signal frequency is 2.6 GHz with a chosen amplitude of -
30 dBm. As already mentioned the impact of the LO power on the receiver
gain is neglected. The third part of the figure shows the signal at the first
mixer output, where the RF signal is mixed down to 2.6 GHz and amplified
by 24 dB. Another mixing product lies at 7.8 GHz but remains unconsidered.
The inphase output with an amplitude of about 4 dBm is shown last. This
DC signal is not filtered because only a lowpass filter is used in the receiver
model.
Summary :
Oscillator parameters Parameter Value Output frequency (Hz) 2.6G Output power (dBm) -30 Output impedance ( ) 50 Noise floor (dBc/Hz) -150 Frequency point f1 (Hz) 2M Phase noise at f1 (dBc/Hz) -103 Corner frequency (Hz) 0 Phase shifter Table 10-8 shows the properties of the phase shifter which combines a shifter and a signal splitter.
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signal,output,ghz,phase,dbm,shifter,receier,pss,table,shows,simulation,amplitude,noise