Transcript Analog and Digital Recording

Analog and Digital Recording
• Audio Recording
– Analog signals
– Digital signals
010101100
What is Audio
• Vibrations of air movements
• Varying strength in amplitude and
frequency
– 1 cycle per second represents a complete
fluctuation
– 20 Cycles (hertz) per second is the lowest
hearing frequency of the human hearing
– 20,000 Hz is the highest frequency we can hear
Analog recordings
•
•
•
•
Have the truest representation of sound
loose quality as each copy is made
recreating the signal is difficult
all sound recording starts and ends analog
– into microphone or pickup
– out of speakers or television
Digital recording
• Converts analog to digital signal
• The process is called Digitizing
• Turns sine wave into digital 1’s and 0’s
Each pulse represents a voltage which is then turned into
a binary code representation
Sampling Rate
• This rate determines how accurate the
signal is interpreted
• The higher the quality, the faster the
sampling rate
– I.e. If the manufacturer uses a sampling rate of
44,000 or 44K Hz, that is fast for a digital signal.
– Most Digital editors can sample this fast
Bit representation
• Represents the amplitude of the analog
signal
– The higher the number of the bits, the better
the represented signal
– 10 bit is better than 8 bit etc.-
Digital Video
• The most dramatic use of digital is in video
recording
• Digital signal represents:
– Color (hue)
– Intensity (strength of light) or saturation
– Brightness (amount of light)
The CCD
• Designed to convert light into electrical
signal
• Uses tiny photovoltaic cells within CCD
• The greater the number of pixels (cells), the
higher the quality of the signal
• Size of CCD affects lens characteristics
• Number of CCD’s affects quality
Prism Block
• Uses the natural properties of a prism
block to redirect the colors of light to each
CCD
• Three primary colors
• One CCD for each primary color
Digital Standards
• Needed for creating universal standards
within the television industry
• IEEE 1394 sets guide lines for all standards
• Commonly called firewire
• Allows interconnectivity of camera to other
digital devices
– VCR’s
– Editors
Steps in converting light into electrical signals
• CCD voltage to processor
– Designed to process signals into 60 fields per
second and 30 frames per second
– Sets beginning of frame and sends to amplifier
• Ampifier to:
– view finder
– to A/D converter
• A/D converter to tape and outputs