Appeal No. 97-0780
Application 08/330,265
The disclosed invention pertains to a method and apparatus for simulating an RF
multipath propagation channel. Such channels are known to suffer from problems of delay
spread of the received signals, different attenuation properties of the multiple paths, and
the Doppler shift of signals induced by movement between the transmitter and the receiver.
A particular feature of the disclosed invention is that RF signals are written into memory at
a first frequency and read from memory at a second frequency, which frequencies are
related so as to simulate the Doppler shift of the signals.
Representative claim 1 is reproduced as follows:
1. A method for simulating an RF propagation channel, comprising the steps of:
inputting an RF signal (fin) to a simulator;
sampling the RF signal and writing a sample to a memory means at a write
frequency (fw);
storing said sample in the memory means; and
reading the sample from the memory means at a read frequency (f ) after a delay
Ri
time (t ) from writing the sample to the memory means;
di
wherein the delay time (t ) corresponds to a delay for the RF propagation channel
di
and the difference between the write frequency (fw) and the read frequency (f )
Ri
corresponds to a Doppler shift in the frequency of the RF signal (fin) for the propagation
channel.
The examiner relies on the following reference:
Argo et al. (Argo) 5,191,594 Mar. 2, 1993
2
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