Audio recording. Radio stations rely on different types of digital recording systems to store audio and play out programme material. In digital recording, the signal is recorded in digital form in which the original electrical variations are represented by series of pulses or bits of information. Audio in bit form is rather like words typed on a computer; both can easily be manipulated. The sound quality remains exactly the same as the original and, unlike analog tape copies, does not degrade as successive digital copies are made. With vast amounts of digital storage becoming cheaper, a revolution has taken place in way radio stations all across the world operate. India should be no exception, as and when the government allows the private FM stations to broadcast news.

Digital recording hardware includes:

• Portable hard disk. The new generation of location recorders. They are small, rugged and robust portable recorders which capture audio on a small memory card. Recordings can be digitally edited on location if necessary and played back via ISDN, mobile phone or wireless internet devices.
• Flashmics. Microphones with a self-contained digital audio recorder. Highly portable and easy to use with a jack for headphone monitoring and playback.
• Minidiscs. Smaller, recordable compact discs usually capable of holding more than 70 minutes of fully indelible, instantly accessible sound. They are used mainly by commercial radio stations' reporters in many countries and can be rough-edited in the field. Both minidiscs and digital cartridges have their own digital players, usually with a large rotary control on the front to select the desired track. A digital display shows the title of the track selected and its number. However they use digital compression, so the quality will degrade with successive copies.
• Digital cartridges. A disk is used to digitally record and play back. Usually, a digital cart (or D-cart) carries various items such as clips, jingles and commercials. It does not need to be rewound so any of its tracks are instantly accessible.
• Digital Audio Tape (DAT). For short was once welcomed as the industry standard, although it has been superseded by the more rugged location and studio systems described above. DATs are smaller in size than analogue cassettes and use the same technology as video recorders, a slow speed tape scanned by a revolving head.
• Computer hard disk. A studio based system with a fully interactive massive memory capacity used by most radio stations in the world now, to store all audio from music to jingles, commercials to news clips. Hard disk is the best way to make quality material instantly available to a number of users. Once audio is loaded on the system as data, any number of individuals can access it simultaneously and independently stop it, start it, edit it or put it on pause, all without any denigration in quality. Because it is computer data, it is also instantly accessible. The BBC standard is RadioMan, commercial radio stations in the UK and the US as well as in India have adopted half a dozen other options such as RCS, Enco DAD and AudioVAULT.

Audio editing. Audio often has to be edited before transmission to remove unwanted parts of a recording. In an interview, people tend to cough, pause, make false starts and other mistakes; all these events are annoying for the listeners, and if left untouched, would waste invaluable time in a news bulletin. This can be improved in following ways:

Digital editing. The audio is transferred on to hard disk of a newsroom or radio station computer system. Using suitable software, one can view the data as a waveform. By using a mouse to point and to highlight the relevant sections of audio, one can cut and re-order the material. One will be able to zoom into certain parts of the recording to make exact edits, and of course, one is able to hear what they sound like before one makes the cut. The golden rule is to use one's ears and not one's eyes.

The modern bulletin desk. Most computer systems take in text and audio on international stories via satellite from news suppliers such as the BBC's GNS (General News Service), Associated Press and Reuters. A typical system is that used at BBC stations ' ENPS ' which is integrated with an audio editor (Quick Edit Pro) and play out system (RCS).

ENPS automatically sorts and stores text into specifically designated folders allowing quick scanning of stories. One can rewrite copy and save it locally, and then use it to compile a bulletin or programme. ENPS allows one to search the wires for stories, and see the running orders at other radio and television stations on one's own network almost anywhere in the world. Material can be printed for reading in the traditional way or read off screen with audio activated either by a mouse, keyboard or touch screen. After the bulletin, copy and audio is archived and items from freelancers are automatically brought to the attention of the radio station's accounts department for payment. Most systems also have the storage capacity to contain comprehensive and updated lists of contacts to which everyone in the newsroom has access.

Studios

• Play out systems. Most computerized play out systems work in basically the same way. They make an audio log of everything that goes out on air. This is saved in files whose names correspondent with the different programmes, so it is easy to find and then clip an interviews that has just been transmitted. This is usually the job of the bulletin editor or news reader. By loading up the waveform of the programme into Quick Edit Pro they can find, name and save a clip. The cue to that clip can then be written, using the same slug, and entering the clip details (name, duration, in and out words) in the appropriate window.
• Equipment. A radio studio uses a number of sources of sound. These can include, microphones, digital hard disk play out system, CDs and mini disks, phone lines, ISDN lines, high speed internet connection

A studio mixing desk allows all these sources to be combined into a broadcast signal and sent to the transmitter. Which sources are present depends on the purpose of the studio. Most news studios are operated by the news presenter throughout the bulletin (a self-opt studio). They will read the stories, play in audio clips, and bring in other outside sources such as a reporter on an ISDN line from a cricket ground.

The modern news studio contains at least one microphone, audio recording and play out system, access to incoming sources (such ISDN or telephone lines) and a small mixing desk, to combine these sources to air. Such a studio can be used not only for live bulletins but also for recording interviews (either from a telephone line, ISDN or in the studio), dubbing interviews onto the hard disk from a portable recorder, recording packages and editing. A second microphone makes live voices much easier, using a reporter in the studio with the bulletin presenter.Many news studios, especially in commercial radio; now include an audio processor to help boost the punchiness of the sound not only from the microphone but also from other sources to make output more consistent. Some studios intended for programmes as well as bulletins are arrange around a round table with microphone leads fed through centre whole. The presenters sit on one side of the table with a line of sight to the production team while guests have their back to the control room next door. This is sometimes helpful when the presenter needs a visual indication that the interview should be wound up. The news studio, booth often has a direct line of sight with the main on-air studio. Failing this, a CCTV camera may be in operation between the two, mainly so the presenter can be sure the newsreader is there before they introduce the bulletin. Either way, a talk back system is always in operation, allowing off-air communication between the two sound-proofed studios while audio is being broadcast.