INTRODUCTION Pulse Modulator TF 2169 is designed to be used in conjunction with a signal generator to produce high quality pulsed r.f. signals. The modulator requires two inputs : the r.f. carrier from a signal generator and a pulse waveform from an external pulse generator. The pulsed r.f. output is taken via a built-in step attenuator. The modulator is primarily designed for use with Signal Generator TF 2015 so it is dimensioned and constructed to be easily fitted to the underside of TF 2015 such that the combination appears as a single instrument. It can also be used with other signal generators similar to TF 2015 in frequency range, output impedance, output level etc.