3MHz function generators have built-in frequency counter

The revised TG300 series from TTi (Thurlby Thandar Instruments) is a range of three function generators with a maximum frequency of 3MHz and which provide simultaneous digital display of frequency and level. The new models are housed in the company’s latest 2U high bench instrument case.

The TG300 series can generate sine, square, triangle, pulse and ramp waveforms from 0.03Hz up to 3MHz. Variable bi-directional symmetry with constant frequency is provided over a ten to one range. An external sweep input allows the frequency on each range to be varied by at least 1000:1.

Auto-ranging reciprocal frequency measurement gives 4-digit resolution with rapid update right down to 2Hz. Accuracy is within ±1 digit (±0.03% at full scale). To maintain a fast update below 2Hz, the measurement mode is changed resulting in 3-digit resolution. When compared to the normal fixed gate-time meters used in other products the TG300 series provides both higher accuracy and faster display update across the whole frequency range.

The output level display can be selected to show any of three values: peak to peak amplitude, rms amplitude or DC offset. The decimal point and units are changed automatically resulting in a display of the true amplitude regardless of the attenuator setting.

Each generator provides a main output with a maximum emf of 20V pk-pk from a 50 Ohms or 600 Ohms source. An amplitude vernier with a range of 20dB is combined with two switched attenuators of -20dB and -40dB to provide levels down to 2mV pk-pk unterminated.
Variable DC offset of ±10V is available via a centre detent control. An auxiliary output provides a fixed 0V to +5V level suitable for driving both TTL and CMOS loads

The top model in the series, the TG330, has a built-in sweep generator providing linear or logarithmic sweeps with periods ranging from 20ms to 20 seconds. AM capability is also incorporated with a choice of internal or external modulation from 0 to 100%.