QPSK (Quadrature Phase Shift Keying) is a phase modulation algorithm. Phase modulation is a frequency modulation version where the carrier wave’s phase is modulated to encode bits of digital information in each phase change. The “PSK” in QPSK refers to the use of Phased Shift Keying. Phased Shift Keying is a form of phase modulation that is accomplished by using a discrete number of states. QPSK refers to PSK with 4 states. With half that number of states, there is a BPSK (Binary Phased Shift Keying). With twice the number Read More

An iPad is a tablet PC that Apple produced. It combines the functionality of a smartphone, laptop, e-reader, and music player. iPads are larger than smartphones, but smaller than laptops and are extremely lightweight and portable. iPads are based on touch screen technology and include support for Bluetooth, WiFi, and 3G. iPads also include motion detection and automatic brightness adjustment, and some models are equipped with both front and back built-in cameras.   iPad Dimensions The original iPad is 9.56 inches long, 7.47 inches wide, and .5 inches thick. The Read More

To customize one’s default homepage on Google Chrome, one will need to adjust one’s homepage settings. To do so, follow these instructions: 1. Click the Wrench icon on the browser toolbar. 2. Select Options (Preferences on Mac and Linux or Settings on a Chromebook). 3. Click the Basics tab. 4. To set the homepage, select either the New Tab page in the “Home page” or select “Open this page” to enter a web address for a page that one would like to use. 5. It is also important to go Read More

The M4A music or track file extension is the default Apple file extension used for music stored in MP4 format on the iTunes multimedia player. Apple deployed the file extension in order to allow iDevices to more quickly recognize what type of MP4 file was being loaded (video or audio) in order to create a faster load time and better end-user experience when playing music stored in this format. For users who have one or many songs store in the legacy MP3 format, a common task that arises is converting Read More

Since the early 1990s and the introduction of Linux as a free operating system, more and more open software and file formats have become available, culminating in a commitment from Microsoft, the world's biggest closed source supplier, to support an open file format for exchanging information in document format. Docx is one of their first contributions. Open file formats such as docx are important because they allow people to share documents even if they aren't using the same software that was used to create the original document. This makes it Read More

The term public domain refers to the point in time when intellectual property is no longer protected by national or international copyright law. Once the property in question enters the public domain, others may reuse the work for free. There are three primary reasons that result in intellectual property entering the public domain: 1 – The creator of the work failed to complete the requirements of copyright in his or her country within specified guidelines in relation to the publishing date of the work, 2- The work was completed by Read More

A rectifier changes alternating current into direct current. This process is called rectification. The three main types of rectifier are the half-wave, full-wave, and bridge. A rectifier is the opposite of an inverter, which changes direct current into alternating current. Half-Wave Rectifier The simplest type is the half-wave rectifier, which can be made with just one diode. When the voltage of the alternating current is positive, the diode becomes forward-biased and current flows through it. When the voltage is negative, the diode is reverse-biased and the current stops. The result Read More

Low Earth Orbit (LEO) refers to a satellite which orbits the earth at altitudes between (very roughly) 200 miles and 930 miles. Low Earth Orbit satellites must travel very quickly to resist the pull of gravity — approximately 17,000 miles per hour. Because of this, Lowe Earth Orbit satellies can orbit the planet in as little as 90 minutes. Low Earth Orbit satellite systems require several dozen satellites to provide coverage of the entire planet. Low Earth Orbit satellites typically operate in polar orbits. Low Earth Orbit satellites are used Read More

The phases of the moon are caused by the location of the moon in relation to the Earth. In other words, as the moon rotates around the Earth, sun hits it in different angles and therefore, this causes the moon to undergo different phases. Based on the time of the month, the side of the moon that we see will experience more sunlight on it and then less sunlight. The Phases of the Moon When the moon "starts" its cycle of phases, it is known as a New Moon. This Read More

Single Sign-On is a term which describes an enterprise-wide identity management system. In a Single Sign-On system, each user has one username and one password for all of the systems, devices, and applications to which she has access. The two methods utilized by Single Sign-On systems to do this are: Password synchronization – The Single Sign-On system copies the username and password configuration to each system Centralized account management – Each system is configured to query a central database for user authentication and authorization Single Sign-On systems have the promise Read More