  Synchronization by exchange of pulses is a widespread phenomenon, observed in
flashing fireflies, applauding audiences and the neuronal network of the brain.
Hitherto the focus has been on integrate-and-fire oscillators. Here we consider
entirely analytic time evolution. Oscillators exchange narrow but finite
pulses. For any non-zero time lag between the oscillators complete
synchronization occurs for any number of oscillators arranged in interaction
networks whose adjacency matrix fulfils some simple conditions. The time to
synchronization decreases with increasing time lag.
