Function generators

[netdudeuk]

I'm interested in how many amateur electronics enthusiasts use function generators, what the specifications are and for what purpose.

Is something like this

http://www.ebay.co.uk/itm/2MHz-Dual-Channel-DDS-Function-Signal-Generator-Sine-Square-Wave-Sweep-Counter-/291250699525?pt=UK_BOI_Electrical_Test_Measurement_Equipment_ET&hash=item43cfe4fd05

or this

http://www.ebay.co.uk/itm/New-DDS-Function-Signal-Generator-Module-Sine-Square-Sawtooth-Triangle-Wave-/281225637298?pt=UK_BOI_Electrical_Test_Measurement_Equipment_ET&hash=item417a5aadb2

any good for anything at all ?

[abaxas]

http://www.ebay.co.uk/itm/New-10MHz-Dual-Channel-DDS-Function-Signal-Generator-Source-Frequency-Cymometer-/311104863686

Seams liike there is a 10mhz version for 11 quid more..

I guess they are just those cheapo dds doodars in a nice box?