Function Generator Sweep option

The sweep function will set the generator to automatically sweep across a range of frequencies (usually programmable in some way).

For instance, setting the sweep range for 100Hz to 1kHz with a sweep time of 10msec will cause the generator to output a signal starting at

100Hz, increasing to 1kHz in a time of 10msec.

This is extremely useful for evaluating circuits across their expected frequency range (and especially filters, although that's only one possible target) for amplitude and phase response, amongst other things.

There are many uses for sweep generators, which is why the functionality for them varies widely. Read the data sheets closely to see just what is available on the units you may be interested in.

Cheers

PeteS

across

at

expected

I see. Thanks.

I need a function generator with 50 volts. Normal ones only have

9 volts. Why do they limit it to just 9 and how much difficult to make it 50 or so.

Another thing. Suppose I set the function gen to 10Hz Sine Wave.. and I use some coils in the output, can the coil produce magnetic fields?

D.

It not only can, you would be hard put to prevent it. But how much field strength do you need?

Suppose my function generator has 10 volts maximum. Can I use an external 50 volts to ride on the 10 volts signal so that the ouput of the external 50 volts is tuned in to say the 20 hz sine wave (or other waveshapes) of the function generator?

D.

The limit of the outpu voltage range is generally mostly limited by the operating voltage used in the function generator. That 9V output voltage can be easily generated with +-12V power supply. That's the operating voltage range the ICs used in function generally work. Around +-12V supply is suitbale for many operational amplifier ICs. So there is good selection of suitable output amplifier ICs for that voltage range available.

If the funtion generator maker would have wanted higher output voltage range, he would have needed to use higher operating voltages inside the device and possibly needed much more special ICs to implement it. This would have made the function generator propably considerably more expensive.

If ou have a suitable amplifier that has this output voltage rating, and amplification of 6 or more, you will get the voltage you need by just feeding the function generator signal to it and get the suitable signal level from output. Make sure that the amplifier you have can properly work at the frequencies you need signals at, the bandwidth of amplifier should be considerably higher then your needed frequency if you want to avoid the amplifier to distort your triangle and square wave signals.

High voltage amplifier circuits that can operate from DC to high frequencies tend to be expensive.

If you operata at normal audio frequencies (20 Hz to 20 kHz), a suitable hifi amplifier could be one possibility as the amplifier. If you want 50V output voltage, you would need to select a quite powerful PA amplifier.

50V to 8 ohms is 312.5W and when connected to 4 ohms power is 625W. If you use norma audio amplifir, you would be looking for amplifier in the voltage range.

Other amplifiers when working with audio frequencies could be propably those amplifiers designed to drive distributed speakers that connect to 70V or 100V line. Those should nicely drive 50V to output when not in full power.. Size the amplifier based on the power you need. This kind of amplifiers has limitations on bandwidth (no lowest bass and the highest audio frequencies coudl be attenuated).

If your current needs on output are low and you don't need very low frequencies / DC output, then in some cases just a suitable step-up transformer connected to the output of function generator could work. Or at somewhat higher powers, a normal audio power amplifier (several watts to tens of watts) driving a suitable step-up transformer could be one way to do things. I have used the audio amplifier + transformer when I needed to generae quite high voltage telephone ring signals at

A suitable coil connected to function generator will generate a magnetic field.

--
Tomi Engdahl (http://www.iki.fi/then/)
Take a look at my electronics web links and documents at 
http://www.epanorama.net/