Budget function generator has full digital control

The TG420, new from TTi (Thurlby Thandar Instruments), is a low-cost 20MHz sweep/function generator with full microprocessor-based digital control and an RS232 interface.

The TG420, new from TTi (Thurlby Thandar Instruments), is a low-cost 20MHz sweep/function generator with full microprocessor-based digital control and an RS232 interface.

Unlike most lower-cost function generators, which use a technology that enables them to operate up to no more than a few megahertz, the TG420 uses an alternative technology which retains its waveform quality right up to 20MHz.

The heart of the TG420 is a microprocessor which provides complete control of all the generator functions.

A 'spin wheel' rotary encoder is used to change values which are displayed on the backlit alphanumeric display.

Digital control enables full programmability via 30 setups stored within the instrument or via the RS232 interface.

When improved frequency accuracy is required, the TG420 can be placed into 'frequency lock' mode.

The generator frequency is then continuously compared with an accurate reference and adjusted accordingly.

The TG420 has a built-in generator for linear or logarithmic sweeps.

Start and stop frequencies are independently adjustable, and sweep rate can be set between 20ms and 20s per sweep.

An external modulation input provides for AM or FM modulation at up to 100% from DC up to 50kHz, or for externally controlled sweeps.

The TG420 provides a main output with a maximum EMF of 20V peak-to-peak from a 50ohm source.

Amplitude control of 26dB is combined with two -20dB switched attenuators to provide levels down to 10mV peak-to-peak.

Variable DC offset of +/-10 V is available.

An auxiliary output provides a fixed 0 to +5V level suitable for driving both TTL and CMOS loads.

An RS232 interface is included which accepts remote control commands and can be used with the optional Windows based PC-420 software.

This provides graphical control of the generator including control simulation, configuration files, and automatic test sequences.

The TG420 costs GBP 249 (plus VAT) in the UK.

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