Bipolar square wave to two level square wave

#BIPOLAR SQUARE WAVE TO TWO LEVEL SQUARE WAVE GENERATOR#

Note in Figure 2 that each individual C-R high-pass filter stage tends to pass high-frequency signals, but rejects low-frequency ones.

Third-order, high-pass filter used as the basis of a phase-shift oscillator. Here, three identical C-R high-pass filters are cascaded to make a third-order filter that is inserted between the output and input of the inverting (180В° phase shift) amplifier the filter gives a total phase shift of 180В° at a frequency, fo, of about 1/(14RC), so the complete circuit has a loop shift of 360В° under this condition and oscillates at fo if the amplifier has enough gain (about x29) to compensate for the filterвЂ™s losses and, thus, give a mean loop gain fractionally greater than unity.ДЇIGURE 2. The simplest C-R sine wave oscillator is the phase-shift type, which usually takes the basic form as shown in Figure 2. The frequency-selective feedback network usually consists of either a C-R or L-C or crystal filter practical oscillator circuits that use C-R frequency-selective filters usually generate output frequencies below 500 kHz ones that use L-C frequency-selective filters usually generate output frequencies above 500 kHz ones that use crystal filters generate ultra-precise signal frequencies. If the gain is below unity, the circuit will not oscillate, and if greater than unity, it will be over-driven and will generate distorted waveforms. The second requirement is that the amplifierвЂ™s gain must exactly counter the losses of the frequency-selective feedback network at the desired oscillation frequency, to give an overall system gain of unity, e.g., A1 x A2 = 1. Essential circuit and conditions needed for sine wave generation. Thus, if the amplifier generates 180В° of phase shift between input and output, an additional 180В° of phase shift must be introduced by the frequency-selective network.ДЇIGURE 1. First, the output of its amplifier (A1) must be fed back to its input via a frequency-selective network (A2) in such a way that the sum of the amplifier and feedback network phase shifts equals zero degrees (or 360В°) at the desired oscillation frequency, i.e., so that xВ° + yВ° = 0В° (or 360В°). To generate reasonably pure sine waves, an oscillator has to satisfy two basic design requirements, as shown in Figure 1.

#BIPOLAR SQUARE WAVE TO TWO LEVEL SQUARE WAVE GENERATOR#

Next monthвЂ™s edition of the series will deal with practical multivibrator types of bipolar waveform generator circuits. This monthвЂ™s installment describes practical ways of using bipolars in the linear mode to make simple, but useful sine wave and white-noise generator circuits. The two most widely used types of transistor waveform generator circuits are the oscillator types that produce sine waves and use transistors as linear amplifying elements, and the multivibrator types that generate square or rectangular waveforms and use transistors as digital switching elements.

Bipolar square wave to two level square wave