Question

Please give brief descriptions and examples with diagrams on

envelope in signal
txco
vccio

Answer 1

first of all for a signal, amplitude and the frequency are the two important parameters which decides the type of signal and the power it carries.

while the frequency of the signal is shown by itself, the envelop is the outer lining of an modulated or unmodulated signal which represents the amplitude of it. as shown below.

Now TXCO(temperature compensated crystal oscillator). Let's see why we need a TXCO and how different it is and what it does. normal crystal oscillators do provide the oscillatory voltage with enough accuracy. but when you use this crystal oscillator at an environment in which the temperature changes randomly and rapidly, thus changing the frequency of oscillator. since the electric charges do get the drift velocity from any energy they can get. So as temperature changes, electrons get the excitation from temperature and thus might cause frequency and amplitude variations in the signal being produced by the oscillator. these changes are what we don't desire. So we design an oscillator which is immune to temperature changes by connecting a capacitor peak detector and a high pass filter to the crystal oscillator. this filter wont allow the undesired frequency changes to pass on and the peak detector will maintain the amplitude.

Unfortunately all the TXC oscillator circuit diagrams are copyrighted and I cant provide copyrighted content here.

Now, VCCIO commonly known as processor power for I/O which is the voltage for integrated memory controller as well as the PCI-E controller, VCCIO (commonly known as VTT/QpI) is the IMC Voltage and helps in stabilizing when RAM is being overclocked. This is the one that feeds the integrated memory controller on processor which have IMC. but now a days the VCCIO is voltage for (I/O) pins of the CPU, except memory-related pins.