Why Isn't My Raltron Crystal Oscillator Causing the Diode to Blink?

[David lopez]

I bought a raltron crystal oscillator.
I connected it to a programmable frequency divider. It is supposed to cause a diode to blink on and off. The crystal oscillator has a rated frequency of 100 megahertz. The programmable frequency divider can divide a frequency by up to 2,147,483,648. Diode won't blink. How do I troubleshoot the crystal oscillator?

 

[Averagesupernova]

How do I troubleshoot the crystal oscillator?

Without an oscilloscope, you won't.

 

[berkeman]

How do I troubleshoot the crystal oscillator?

Can you post your schematic and a picture of how you hooked it up?

Also, it's probably best to start with an oscillator around 1MHz (or even 32.768kHz), to make the circuit easier to deal with. Circuit construction around 100MHz takes specialized techniques that you can learn later.

 

[davenn]

Diode won't blink.

if the oscillator frequency is more than around 50Hz, then you won't see it blink
It will be too fast for your eye to see

 

[David lopez]

Can you post your schematic and a picture of how you hooked it up?

Also, it's probably best to start with an oscillator around 1MHz (or even 32.768kHz), to make the circuit easier to deal with. Circuit construction around 100MHz takes specialized techniques that you can learn later.

What are these specialized techniques?

 

[davenn]

What are these specialized techniques?

VHF (very high frequencies) and up require careful circuit layout and construction
so that they work correctly ... for example
1) .. they cannot be built on those solderless breadboards ( like you have been using)
2) .. interconnecting wiring between components must be kept as short as possible
because if they are too long they can become significant inductance or become antennas
3) .. shielding between stages/sections
4) the use of feedthrough capacitors and ferrite beads to stop RF getting back out onto
power supply lines

the list goes on ...

Now that is just some of the construction issues
Testing is another whole ball game. Suitable test gear for the frequencies being experimented with
are essential ( now that goes for all circuits but becomes more critical as the frequencies increase)
As the frequencies increase, the cost of good/reliable test gear also increases.
I have many $1000's of test gear here that I use on VHF, UHF and into the microwave bands
up to 24 GHz
Spectrum analyser to make sure a signal is clean -- no harmonics present or at least very reduced
RF power meters to know how much power is being produced
Frequency counter(s), I have 3 for different uses, to make sure you are producing a signal
on the correct frequency
Decent quality, high impedance, multimeter
Decent oscilloscope for looking as waveforms etc of various signals

again, the list goes on as you get more into it...

 

[David lopez]

So I should avoid using a solderless board?

 

[berkeman]

So I should avoid using a solderless board?

At 100MHz? Yes, please avoid that.

 

[David lopez]

Why can't they be built on solderless
Boards?

 

[berkeman]

Why can't they be built on solderless
Boards?

2) .. interconnecting wiring between components must be kept as short as possible
because if they are too long they can become significant inductance or become antennas

3) .. shielding between stages/sections

the list goes on ...

Basically, you need to control parasitics (capacitance, inductance, coupling) very carefully in high-frequency circuits. A wire is not just a wire, it's an inductor and an antenna. A capacitor is not a capacitor anymore, the parasity inductance associated with it makes it a tuned circuit. An inductor is no longer an inductor, its parasitic capacitance shorts out much of the inductance...

the list goes on ...

 

[berkeman]

Here is a good book that describes the digital side of high-speed design. It was written by a very bright guy who used to work at the company that I still work for. Our CEO bought copies for every hardware engineer in the company when Howie first published it... See if your local technical library has a copy that you can look through...

 

[David lopez]

I am planning to buy a microchip that
Contains a voltage controlled oscillator
Rated at 2.4 gigahertz that will work on a breadboard?

 

[davenn]

I am planning to buy a microchip that
Contains a voltage controlled oscillator
Rated at 2.4 gigahertz that will work on a breadboard?

what do you think in the light of what you have been told in the above posts ?

 

[davenn]

Contains a voltage controlled oscillator
Rated at 2.4 gigahertz that will work on a breadboard?

ohhh ... and do you have a frequency counter that goes to at least 2.5 GHz
so you know the exact frequency you are radiating RF energy on ?

If not, don't get the oscillator module till you have spent good money on a frequency counter first

 

[David lopez]

How do prototype circuits that contain this chip?

 

[davenn]

How do prototype circuits that contain this chip?

a PCB .. Printed Circuit Board

 

[David lopez]

Is that the only way?

 

[anorlunda]

The original question has been answered.

Thread closed.