equipment is suitable for testing other types of receivers fig1 shows test apparatus 1 suitable for simulating different signal propagation environments within which a receiver e g a radiotelephone may be required to operate thereby allowing the sensitivity of a receiver to be tested for the different environments under which the receiver may operate typically the sensitivity of a receiver is measured by measuring the ber of a signal received by the receiver however other types of measurements may be used for example frame error rate fer the main causes of signal variations that result in a receiver being unable to accurately recover data are channel noise interference and multipath propagation the test apparatus 1 includes a signal generator 2 and a channel model 3 the signal generator 2 is coupled to channel model 3 which in turn is coupled to radiotelephone 4 a test unit 5 is coupled to radiotelephone 4 and signal generator 2 the signal generator 2 simulates a transmitter for example a base station in a cellular network however to minimize emitted rf radiation the signal generator preferably generates a simulated rf signal the signal can however be transmitted as an i and q signal a rf signal or an intermediate frequency signal the signal generator 2 provides a test signal 17 to channel model 3 either as a simulated rf signal i and q data an intermediate frequency signal or as a transmitted rf signal as described above the test signal 17 incorporates a pseudorandom bit sequence the channel model 3 simulates the communication channel between a basestation and.