High speed sine wave to square wave converter

In summary: That's definitely high speed. What is the source of the 1.5GHz "square wave"? What are the rise and fall times? Is the source impedance 50 Ohms? You may get a lot of irrelevant answers if you aren't a bit more detailed about your application. I have a feeling that the useful answer may be that you may not need to have a square wave.I think skeptic's overdriven amplifier/switch approach is the likely to be the most fruitful.
  • #1
thavamaran
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Hi guys, I need to convert a sine wave to square wave, sine wave is running at about 1.5 GHz, so I had an idea of using comparator, but I am afraid that most of the conventional op-amps can't support my speed requirement.

Any advice and reference circuits please.
 
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  • #2
thavamaran said:
Hi guys, I need to convert a sine wave to square wave, sine wave is running at about 1.5 GHz, so I had an idea of using comparator, but I am afraid that most of the conventional op-amps can't support my speed requirement.

Any advice and reference circuits please.

That's definitely high speed. What is the source of the 1.5GHz "square wave"? What are the rise and fall times? Is the source impedance 50 Ohms?

What are you going to do with the "sine wave"? What THD can you tolerate? What is the load impedance? Can you just use a bandpass filter at 1.5GHz?
 
  • #3
Hi berkeman, the description that you are giving sounds like square to sine. What I need is sine to square, I am using an Agilent vector signal generator to generate sine wave at 1.5 GHz, so I need to convert this to square 1.5 GHz.
 
  • #4
thavamaran said:
Hi berkeman, the description that you are giving sounds like square to sine. What I need is sine to square, I am using an Agilent vector signal generator to generate sine wave at 1.5 GHz, so I need to convert this to square 1.5 GHz.

Ah, apologies for my misread.

So, what are you going to do with the square-ish wave? What edge speeds do you need? What amplitude sine are you starting with, and what amplitude square wave do you want? If you can start with enough amplitude on your sine wave, you could use diode clamps to flatten off the tops...
 
  • #5
Is there any logic family that works at that frequency these days? There must be, but I haven't been following the industry. If so, and your sine wave voltage was appropriate, you could probably just use an inverter or buffer device. For that matter an RF transistor in a common-emitter config might just do the trick...
 
  • #6
berkeman, no worries, thanks a lot for replying...

Im going to use this square-ish wave to function as battery for biasing device. I actually need a rectangular pulse with on-time 1ns and off time 1ns which the frequency is 500 MHz, so I just explain as 1.5 GHz cause in future I might increase the speed.

Sine wave amplitude is 1.8V and can i get the same for the rectangular? Diode clamps means diode clipping circuit is it? But will diode work this fast?
 
  • #7
schip666!, there is this schmitt trigger which works above 1 GHz (SN74LVC1G17DB). Inverter or buffer?
 
  • #8
Think about it in the frequency domain. In order to get anything close to a square wave you're going to have to create a significant number of odd harmonics. So don't think so much about 1.5 GHz but about maybe 9 GHz. I don't know of any logic or comparators that can do that (they may exist but they'll be expensive).

I'd get some microwave transistors and amplify the sinewave into clipping until I reach the maximum slew rate of the transistors. Using more stages instead of fewer will probably get you a better squarewave and try not to drive the stages too much into saturation or cutoff.
 
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  • #9
thavamaran said:
berkeman, no worries, thanks a lot for replying...

Im going to use this square-ish wave to function as battery for biasing device. I actually need a rectangular pulse with on-time 1ns and off time 1ns which the frequency is 500 MHz, so I just explain as 1.5 GHz cause in future I might increase the speed.

Sine wave amplitude is 1.8V and can i get the same for the rectangular? Diode clamps means diode clipping circuit is it? But will diode work this fast?

It still isn't clear it needs to be a square wave. If you are 'biasing' ("battery") that implies a constant value of voltage. If you are 'switching' / modulating / sampling then the harmonics associated with a waveform that is 'squarer' than your original 'sine wave' will be well out of band.

You may get a lot of irrelevant answers if you aren't a bit more detailed about your application. I have a feeling that the useful answer may be that you may not need to have a square wave.
 
  • #10
  • #11
Making a transistor amp that saturates and comes back out in a few 100 ps sounds pretty crazy. Diodes are far faster and can be saturated, amplified, saturated again, amplified again... There's no such thing as a "clean" square wave at 1.5GHz, but this would get you something without undue pain.

There are also GaAs houses producing flip-flop dividers over 10GHz. If you have source, those could be fairly clean.

Finally, you might look into onsemi's latest generation of ECL. Based on SiGe, these can give good logic edges.

- Mike
 
  • #12
To make any really relevant comment about this is it really necessary to know a bit more about the actual application. I might ask whether this question relates to a practical situation or a simulated one. It's all very well finding a device that will produce this "square wave" when operating into a resistive load of the right value but it's an entirely different matter to say what it's going to look like when fed into a base. I have to ask again, what it is actually needed for and what is the specific need for a square wave.
 
  • #13
Mike_In_Plano that's a pretty good idea. You'd still need several stages of amplification using a higher voltage supply before the diode clipper but the diode clipper would probably give a cleaner square wave.
 
  • #14
skeptic2 said:
Mike_In_Plano that's a pretty good idea. You'd still need several stages of amplification using a higher voltage supply before the diode clipper but the diode clipper would probably give a cleaner square wave.

... when applied to what load?
 
  • #15

1. What is a high speed sine wave to square wave converter?

A high speed sine wave to square wave converter is an electronic circuit or system that converts a sinusoidal input signal into a square wave output signal. It is used to change the shape of the signal, typically for the purpose of amplification or processing.

2. How does a high speed sine wave to square wave converter work?

A high speed sine wave to square wave converter typically uses a comparator, which compares the input signal to a reference voltage. When the input signal exceeds the reference voltage, the comparator outputs a high voltage level, and when the input signal falls below the reference voltage, the comparator outputs a low voltage level, creating a square wave output signal.

3. What are the applications of a high speed sine wave to square wave converter?

A high speed sine wave to square wave converter is commonly used in audio and radio frequency (RF) applications for signal amplification and filtering. It can also be used in digital electronics to convert analog signals into a form that can be processed by digital circuits.

4. What are the advantages of using a high speed sine wave to square wave converter?

The main advantage of using a high speed sine wave to square wave converter is its ability to convert signals quickly and accurately. It also has a wide range of applications and can be easily integrated into electronic systems. Additionally, it has a simple and cost-effective design.

5. Are there any limitations of a high speed sine wave to square wave converter?

One limitation of a high speed sine wave to square wave converter is that it may introduce noise or distortion into the output signal. The accuracy of the output signal may also be affected by variations in the input signal or changes in the reference voltage. Additionally, it may not be suitable for converting signals with very low frequencies or high amplitudes.

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