EP0063485A2
Expired / Lapsed
EP
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Digital data companding
Assignee: Hitachi Ltd
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Filing: 1982-04-16
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Granted: —
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Expires: 2002-04-16
Abstract
Abstract Digital companding without range bits comprising comparison (40) of a digital input with predetermined boundaries separating a plurality of numerical ranges, detection (40) of a numerical range to which the digital input belongs, generation (11) of an off-set unique to each numerical range, bit-shifting (6) of the digital input, and addition (7) of bit-shifted input with the generated off-set to provide companded digital output which is in one-to-one correspondence to the digital input. The off-set values are stored in a memory (11).
Inventors
- 👤 Hiroo Okamoto
- 👤 Takao Arai
- 👤 Takashi Hoshino
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-03 14:49
CPC Classifications
H; H03; H03G; H03G7/00; H03G7/007; H03M; H03M7/00; H03M7/30; H03M7/50
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
132 words
A circuit for transforming a digital input signal into another digital signal of different bits, comprising: a digital input terminal (1) for receiving a digital input signal of a first number of bits; means (40) for classifying the digital input signal and designating it to one of predetermined ranges according to the magnitude of the digital input signal; means (6) for transforming the digital input signal into an intermediate signal of a predetermined scaling assigned to the designated range; means (11) for generating a predetermined off- set value assigned to the designated range; and means (7) for adding said intermediate signal and said off-set value to provide said another digital signal, the off-set value being so selected that said another digital signal varying monotonically with the increase of said digital input signal.
Claim 2
Dependent Claim
132 words
A circuit for transforming a digital input signal into another digital signal of different bits, comprising: a digital input terminal (1) for receiving a digital input signal of a first number of bits; means (40) for classifying the digital input signal and designating it to one of predetermined ranges according to the magnitude of the digital input signal; means (6) for transforming the digital input signal into an intermediate signal of a predetermined scaling assigned to the designated range; means (11) for generating a predetermined off- set value assigned to the designated range; and means (7) for adding said intermediate signal and said off-set value to provide said another digital signal, the off-set value being so selected that said another digital signal varying monotonically with the increase of said digital input signal.
Claim 3
Dependent Claim
14 words
A circuit according to claim 1, wherein said transforming means comprises a shift register.
Claim 4
Dependent Claim
23 words
A circuit according to claim 1, wherein said classifying and designating means includes a memory (10) for storing boundary value of adjacent ranges.
Claim 5
Dependent Claim
30 words
A circuit according to claim 1, wherein said classifying and designating means includes a plurality of comparators (46, 47) which compare the magnitude of input signal with respective boundary values.
Claim 6
Dependent Claim
59 words
A circuit according to claim 1, wherein said classifying and designating means includes a terminal (4) adapted for receiving a control pulse of predetermined timing, a reference signal generator (10) for generating a predetermined reference signal in response to said control pulse, and a comparator (9) for comparing the magnitude of the digital input signal with said reference signal.
Claim 7
Dependent Claim
21 words
A circuit according to claim 4 or 5, wherein said off-set generating means includes a memory (11) storing said off-set value.
Claim 8
Dependent Claim
25 words
A circuit according to claim 5, further comprising a latch circuit (8) connected to said adding means for latching the output of said adding means.
Claim 9
Dependent Claim
134 words
A digital compressor circuit for compressing a digital input signal, comprising: a digital input terminal (1) for receiving a digital input signal of a first number of bits; means (40) for comparing the digital input signal with a group of numerical ranges and designating one of the numerical ranges to which the digital input signal belongs; means (6) for compressing the digital input signal to provide an intermediate compressed signal which has reduced bits when the magnitude is large; means (11) for generating a predetermined off- set value assigned to the designated range; and means (7) for adding said intermediate compressed signal and said off-set value to provide compressed digital output signal, the off-set value being so selected that said compressed digital output signal increasing monotonically with the increase of said digital input signal.
Claim 10
Dependent Claim
134 words
A digital compressor circuit for compressing a digital input signal, comprising: a digital input terminal (1) for receiving a digital input signal of a first number of bits; means (40) for comparing the digital input signal with a group of numerical ranges and designating one of the numerical ranges to which the digital input signal belongs; means (6) for compressing the digital input signal to provide an intermediate compressed signal which has reduced bits when the magnitude is large; means (11) for generating a predetermined off- set value assigned to the designated range; and means (7) for adding said intermediate compressed signal and said off-set value to provide compressed digital output signal, the off-set value being so selected that said compressed digital output signal increasing monotonically with the increase of said digital input signal.
Claim 11
Dependent Claim
117 words
A digital expandor circuit for expanding a compressed digital input signal having no range bit, comprising: a digital input terminal (1) for receiving a digital input signal of a first number of bits; means (40) for comparing the digital input signal with a group of numerical ranges and designating one of the numerical ranges to which the digital input signal belongs; means (6) for expanding the digital input signal to provide an intermediate expanded signal which has increased bits when the magnitude is large; means (11) for generating a predetermined off- set value assigned to the designated range; and means (7) for adding said intermediate expanded signal and said off-set value to provide expanded digital output signal.
Claim 12
Dependent Claim
117 words
A digital expandor circuit for expanding a compressed digital input signal having no range bit, comprising: a digital input terminal (1) for receiving a digital input signal of a first number of bits; means (40) for comparing the digital input signal with a group of numerical ranges and designating one of the numerical ranges to which the digital input signal belongs; means (6) for expanding the digital input signal to provide an intermediate expanded signal which has increased bits when the magnitude is large; means (11) for generating a predetermined off- set value assigned to the designated range; and means (7) for adding said intermediate expanded signal and said off-set value to provide expanded digital output signal.
Claim 13
Independent Claim
140 words
A method of companding a digital input signal omprising the steps of: preparing a plurality of input numerical ranges and an equal number of output numerical ranges, each of the output numerical ranges corresponding to unique one of the input numerical ranges; comparing a digital input signal with boundary values of said input numerical ranges and designating an input numerical range to which the digital input signal belongs; companding the digital input signal according to the scale of an output numerical range corresponding to said designated input numerical range; generating a predetermined off-set value unique to said corresponding output range; and adding said companded digital input signal and said off-set value to provide a biased digital output signal, said off-set value being so selected that said biased digital output signal varying monotonically with the increase of said digital input signal.
Claim 14
Independent Claim
140 words
A method of companding a digital input signal omprising the steps of: preparing a plurality of input numerical ranges and an equal number of output numerical ranges, each of the output numerical ranges corresponding to unique one of the input numerical ranges; comparing a digital input signal with boundary values of said input numerical ranges and designating an input numerical range to which the digital input signal belongs; companding the digital input signal according to the scale of an output numerical range corresponding to said designated input numerical range; generating a predetermined off-set value unique to said corresponding output range; and adding said companded digital input signal and said off-set value to provide a biased digital output signal, said off-set value being so selected that said biased digital output signal varying monotonically with the increase of said digital input signal.
References Cited (Backward Citations)
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