Tx Trigger - Furuno FAR-2107 Series Service Manual

1. TX trigger

Four triggers different in pulse length to each drive circuit of the MD board. These
outputs are combined to create high-voltage TX pulses. The waveform of short and
middle TX pulses is a triangular wave. In signal processing, it allows suppressing
relatively weaker echoes such as sea clutter on short range. The photos below show
examples of waveforms of detected TX output of the X-band/25 kW radar.
The pulse length at the point 3 dB below the peak is defined as the pulse length.
0.18 us
Photo 7.2.1
(e.g.) Waveform of 25 kW S1 pulse TX output
1.32 us
Photo 7.2.3
(e.g.) Waveform of 25 kW L pulse TX output
40 ns/div
200 ns/div
Photo 7.2.2
(e.g.) Waveform of 25 kW M1 pulse TX output
7-9
7.2 Antenna Unit
0.5 us
100 ns/div