Implant Clocking and Timing Circuits
A clock circuit is a redstone circuit (a structure built to activate or control mechanisms). It produces a repetitive pattern of pulses referred to as a clock signal. A clock generator IC can perform various functions. The functions include the generation, conditioning, manipulation, distribution, or control of a timing signal in an electronic system. The output of clock generators is toggling on/off constantly. To build clock generator circuits, a number of oscillator designs exist. These circuits produce sinusoidal or square waves. The frequencies of the waves range from <1 Hz to several MHz. A linear or sinusoidal wave RC oscillator consists of a tuned RC network connected to regenerative feedback amplifier. Sustenance of steady oscillations requires the fulfillment of Barkhausen’s criterion stating that the loop gain at the oscillation frequency must be unity in absolute magnitude and the total phase shift around the loop should be zero or an integral multiple of 180°. RC oscillators for producing waveforms of square, triangular, or sawtooth shapes are often called relaxation oscillators. The term “relaxation” is related to the charging and discharging states of a capacitor. Many types of relaxation oscillators have been built, starting from simple two-transistor multivibrator circuits and advancing to more intricate circuit topologies. All these oscillators work on the same operating principle.
The generated square waves are used to control the timing of operations in digital systems, such as clock generators for microprocessors. These different circuits are known by a variety of names, such as monostable, astable, and bistable multivibrators. The multivibrator functions can be easily implemented with timer integrated circuits. These circuits are therefore extensively used in timing applications.
KeywordsLinear oscillator Nonlinear oscillator Crystal oscillator Monostable/astable/bistable multivibrator Timer IC Time delay Missing pulse detection Frequency division PWM PAM
- 1.Maxim Integrated (2003) Application Note 2154: Microcontroller clock—crystal, resonator, RC oscillator, or silicon oscillator? © 10 Sep 2003. Maxim Integrated Products, San Jose. http://www.maximintegrated.com/en/app-notes/index.mvp/id/2154. Accessed 29 Sept 2014
- 2.Fairchild Semiconductor (1974) CMOS oscillators: Application Note 118 © 1998 Fairchild Semiconductor Corporation, South Portland, 4 p. https://www.fairchildsemi.com/application-notes/AN/AN-118.pdf. Accessed 31 July 2015
- 3.Trudgen G (2009) IC Crystal oscillator circuits. Copyright © 2009 Rakon, 3 p. http://docslide.us/documents/ic-crystal-oscillator-circuit-design.html. Accessed 31 July 2015
- 4.Texas Instruments (2011) AN-400 A study of the crystal oscillator for CMOS-COPS, Literature No. : SNOA676, Copyright © 2011, Texas Instruments, 6 p. http://www.ti.com/lit/an/snoa676/snoa676.pdf. Accessed 31 July 2015
- 5.Storr W (2014) Basic electronics tutorials site: multivibrators. Last updated 5th September 2014, Copyright © 1999−2014. http://www.electronics-tutorials.ws/sequential/seq_3.html. Accessed 7 Sept 2014
- 6.Agarwal T (2014) What are the important multivibrator circuits for pulse generation? http://www.elprocus.com/different-types-of-multivibrator-circuits-for-pulse-generation/. Accessed 7 Sept 2014
- 7.Roon Tv (2010) 555 Timer Tutorial. http://www.sentex.ca/~mec1995/gadgets/555/555.html. Accessed 7 Sept 2014
- 8.Texas Instruments (2014) LM 555 Timer Copyright © 2014, Texas Instruments. http://www.ti.com/lit/ds/symlink/lm555.pdf. Accessed 7 Sept 2014