Radartutorial .euWaveform-Generator
A waveform generator generates the transmitting signal on an IF- frequency. It permits generating predefined waveforms by driving the amplitudes and phase shifts of carried microwave signals. These signals may have a complex structure for a pulse compression. Since these signals are used as a reference for the receiver channels too, there are high requirements for the frequency stability.
Counter
PROM
PROM
Figure 1: an e.g. Block diagram of a waveform generator for a non-linear compressed pulse
Counter
PROM
PROM
Figure 1: an e.g. Block diagram of a waveform generator for a non-linear compressed pulse 1)
The finally waveform is constructed of 2048 discrete voltage steps here.
Its values of amplitude and phase are stored in programmable memories
(PROM's). The processing of an
I & Q-
phase- detector is arranged reverse virtually.
This method of design the transmitting pulses hats got the advantage,
that the waveform is digitally described for a computer-controlled signal
processing. A digital processor unit can execute the
pulse compression now.
1) A very (unusual) low intermediate frequency of 470 kilohertzes was choosen here to visualize the high-frequencies in the schreen-shoots of the oscilloscope.