Ticking Clocks

What are Clocks in Electronics?

In electronics, a clock is both similar and dissimilar to what most people think of a clock in everyday life. A clock is responsible for coordinating all of the different functions of an electronic system, and it does that by measuring time at a certain rate. For any modern computer to function, it needs an accurate clock on it, which helps with networking, assessing whether software is current and so forth.

A clock works in a much more fundamental level than that in a computer, however. The clock in the computer has to provide the time base for the entire system. The clock provides the clock signal, which is a measure that many different systems within a computer or another complex electronic system will utilize to control their actions.

It's important to understand that, for all practical purposes, a computer really has two types of clocks on it. The first type is the clock that controls the various components that the computer uses to perform various functions. This clock doesn't tell anyone what time it is. It merely beats out a reliable, continuous stream of electrical signals that can be used as measures of time and as references that can be used to coordinate different tasks.

The second type of clock is a real time clock, which is detailed further below. The real time clock is the clock that outputs information that a human being can understand. There are several different ways that you can think of this to keep the two straight, though their functions sometimes overlap in a computer.

The real time clock tells you what time of day or night it is and is usually used for networking, security and other purposes. The hardware clock simply provides a sequence of pulses that human beings, unless they actually test the devices, aren't even aware of.

While the hardware clock coordinates the hardware components, the real time clock has more to do with how people actually use their computers. The real time clock ensures that files have the correct save time and dates imprinted on them, that email is dated correctly and so forth.


How Do Clocks Work?

There is an entire system associated with the clock on an electronic device. This system is usually powered by its own battery, as the clock needs to remain accurate when the machine is shut off.

The primary part of a clock circuit is the oscillator. The oscillator contains a crystal that vibrates at a specific frequency and that maintains that frequency when a specific voltage is applied to it. Any clock moves from a high to a low state, which can also be described as an on or off state.

Even though having only two states may make a clock seem simple, it's actually not. An interval of time that corresponds to one high state and one low state is described as a complete clock cycle. Events can be coordinated based on several clock cycles or, in some cases, the clock cycle can be divided up and several different events can take place within the space of one clock cycle.

Utilizing specific types of circuits and clever engineering, electrical engineers can utilize the clocks on computers to perform remarkably complex calculations reliably and consistently.

The real time clock is usually synched with another clock. There are online time services that can provide the current local time, to which the computer can be synched or network time may be determined by a server clock. When the computer is shut down, the small battery in the motherboard keeps the clock running so that, when it is booted up again, it displays the correct time.


What are Timing and Frequency Control Circuits?

Timing and frequency control circuits are responsible for coordinating complex functions on a computer. As one example of this, when devices need to synchronize data transmission between one another, they rely upon the clock circuit to determine when to transmit and when to receive.

Timing circuits are used in numerous different applications in the electronics world. They are, in fact, among the most common types of circuits in general usage. Without them, it would be impossible for many automated functions to be performed, as the timing circuits and the control circuits oftentimes dictate when each of the sub processes will be carried out in relation to one another.


How do Timing and Frequency Control Circuits Function?

Timing and frequency control circuits, at the most fundamental level, function based on simply electronic theory. For example, one common type of timing circuit utilizes a capacitor. The capacitor will be charged at a constant level, producing a predictably increasing voltage. When that voltage reaches a certain level, it can trigger other electronic components to activate a circuit.

Other types of electronic components may be involved in a given timing or frequency control circuit. Resistors may be utilize, comparators are oftentimes utilized in the capacitor example given above and so forth. There many different ways that these circuits can be constructed.

In terms of functioning within a system, the timing and frequency control circuits take a clock signal and determine when to initiate an action or end an action. The clock signal provides a constant measure of time that has very little error.

A timing circuit can be based on any mathematically predictable change in condition in an electronic component. It can be based on the charge in a capacitor, as detailed above, the oscillations in a crystal, the time gleaned from an outside source or anything else that is reliable. Timing and frequency control circuits have specialized components that are used to ensure that the signal is always very crisp and clean. This prevents errors in the system due to incorrect timing.


Overview of the Various Types of Clocks

Below are listed some of the most common types of clocks and how they function. Components that are networked together and, sometimes, entire computers that are networked together, rely upon clocks to provide them with accurate timing information. In one regard or another, all of the different components listed below are part of that and help to keep electronic systems functioning.


What are Bus Repeaters? How do They Function?

A bus repeater is a device that allows two computers to be networked together. They function by connecting the two computers together at the chassis. These are oftentimes utilized to create very powerful computers from several lower powered computers.


What are Clock Conditioners?

Clock conditioners are components that make signals suitable for processing. They can perform a range of different functions, including amplifying a signal, converting a signal to a different form and so forth.


What are Clock Distribution Circuits?

Clock signals need to be distributed to all of the different devices that have to utilize them and that is what a clock distribution circuit handles. Clock distribution circuits are vital parts of any complex electronic system, as they have to be very sharp signals that are very easy for the devices to read.


What are Clock Dividers?

A clock divider is a device that can take an input signal from a clock and produce a different signal based upon the frequency that it receives. It does this through simple division. This allows processes to be coordinated that take multiple clock cycles to complete or that take less than one cycle to complete.


What are Clock Drivers?

The clock driver is located between the source of the clock signal and a receiving load. The clock driver ensures that the clock pulses are sharp and easily interpreted by the load. The clock driver also controls latency.


What are Delay Line Circuits?

A delay line circuit is one that contains multiple electrical components. The device takes a signal and introduces a phase change – a time difference – between the time the signal was input and the time that it is output. The delay time is highly variable on these devices, and can sometimes be set for several milliseconds in length.


What are Direct Digital Synthesizers?

Utilizing a clock set at a specific frequency, a direct digital synthesizer can produce a variety of different waveforms. These are not only used in electronics, they are also used in music and in many other applications.


What are Function Generator Circuits?

A function generator circuit is oftentimes used for testing purposes. Utilizing a clock that is set at a specific frequency, these devices can generate a specific waveform. These can be large-scale devices or they can be IC devices.

These function generators can generate a variety of different signals. Some of the common types include saw tooth signals, square signals, sine waves and more. These are among the most basic types of devices used in electronic engineering and troubleshooting.


What are Phase Frequency Detectors?

A phase frequency detector has two inputs on it, which can receive two different signals. Oftentimes, the device receives one of the signals from an oscillator, which can produce a signal of the user's choice. When the detector locks onto the signals, it can give other electronic components instructions on how to process the signal.


What are PLL Circuits?

One easy way to understand a PLL circuit is to think of it as a phase detector and an oscillator capable of producing various frequencies. These are oftentimes used as control signal generators. They take an input signal of a given phase and produce an output signal that is related to the input phase in a predefined way.

These are very common circuits in technology designed for telecommunications. They are also very common in computers. In digital circuitry, they are typically used to increase the precision of clock pulses, allowing the entire system to function more smoothly and efficiently.


What are PLL Clock Buffers?

A PLL clock buffer can prevent noise from entering into a signal or delay a signal by a specified amount. These serve the same role as standard clock buffers.


What are PLL Clock Drivers?

PLL clock drivers ensure that the signal that devices receive from the clock are clear and sharp. This prevents inefficiencies and errors in the system. Because of the importance of clocks in an electronic system, drivers are necessities.


What are PLL Frequency Multipliers?

A PLL frequency multiplier can take an input signal from a clock and multiply it, outputting a different frequency. These are commonly used in communications circuitry and are also found in a variety of other applications.


What are PLL Frequency Synthesizers?

A frequency synthesizer can take an input signal and use that as a basis to create a new frequency. They can produce a range of different types of frequencies, with sine waves, square waves and others being particularly common. These circuits are oftentimes used in various types of testing equipment and are sometimes used in musical instruments, as well.


What are Real Time Clocks?

On a computer, there are two types of time that are used to perform various functions. The system clock merely puts out electronic pulses at a predictable rate. The real time clock keeps track of the actual time on Earth, allowing the device to perform several important functions.

Another way to think of a real time clock is to think of it as the clock on your computer that measures time in units that a human being can understand: AM, PM and so forth.

The real time clock on your computer keeps what is commonly referred to as the system time. It may also provide the measure by which software is known to be outdated, items are known to have been accessed a certain number of days in the past and provide other important information.


What are Timer Circuits?

Timer circuits are devices that can fulfill a variety of different functions based on the input from a clock signal. They can, for instance, introduce delay, introduce oscillation at specified intervals and so forth. They are very common and are used in everything from the smallest computers to the largest industrial machinery, in various roles.