J

Jam Sync

Jam Sync is a mode available on many time code readers/generators/synchronizers. When jam synching, a TC reader/generator looks at external, incoming time code. It then "jams" or creates new time code based on that signal, identical to the original. There are two reasons for doing this: First, to replace degraded or defective time code. Second, when copying a time code track from one tape to another (mainly for analog tape, where each copy generation degrades the code signal).

Java

To many audio engineers Java means coffee, a drink to get you started in the morning. But to computer savvy people Java is a computer language. Specifically a platform-neutral language that allows developers to write programs (often called "applets") that can run on practically any computer connected to the Internet. In fact, as you've surfed the Web, you've almost certainly been running Java applets. They're incorporated into many of the pages you visit on your virtual journeys, and the software to run those applets is not only part of the Mac OS but is designed to work seamlessly with browsers that support it. Right now, there are thousands of Java applets in use around the world. To see how industries from aerospace to entertainment to real estate to utilities have been employing Java, you can visit the Java Web site.

Jitter

In a digital recorder or sampler, errors in the timing of sample acquisition due to rapid amplitude changes is called jitter (also known as Sample Offset Uncertainty). Jitter introduces some distortion and phase discrepancy into an audio signal. Higher frequencies are more susceptible to jitter than lower. In most modern gear, use of clocked buffers for digital data streams has minimized the effects of jitter.

Jumper

In the music technology game this word classifies as jargon. It is most used to describe a circuit connection in circuit boards that is made by attaching a (usually) small piece of wire between two points. Jumpers are usually used to either modify existing circuits or to provide a way for the end user to make easy changes. Jumpers are often designed so end users can move or remove them to change the configuration of equipment. For example, it is often possible to change a mixing board's auxiliary send from taking its signal out before the fader (commonly used for monitor mixes) to taking it after the fader (commonly used to drive signal processing). Another example would be changing a patch bay from full-normal to half-normal operation. A third example would be changing the SCSI ID on a hard drive mechanism. Jumpers come in varying shapes, sizes, and configurations and are more or less easy to change depending upon the intentions of the manufacturer of the equipment.