AMPLITUDE QUANTIZED SIGNAL TRANSMISSION METHOD

• US 3,725,592 A
• Filed: 12/13/1971
• Issued: 04/03/1973
• Est. Priority Date: 06/13/1967
• Status: Expired due to Term

• Current Assignee: Yutaka Tanaka
• Original Assignee: Yutaka Tanaka
• Inventors: Tanaka, Yutaka
• Primary Examiner(s): Claffy, Kathleen H.
• Assistant Examiner(s): Leaheey, Jon Bradford
• Application Number:
  US05/207,442
• Time in Patent Office: 477 Days
• Field of Search: 179/15.55R,15.55T,15A,15AW,15BA,15BM,15BW 178/DIG.3
• US Class Current: 375/241
• CPC Class Codes: H04B 1/66 for reducing bandwidth of signals; for improving efficiency of transmission H04B1/68 takes precedence
• CPC Class Codes: H04L 25/4917 using multilevel codes
• CPC Class Codes: H04L 5/04 the signals being represented by different amplitudes or polarities, e.g. quadriplex
• CPC Class Codes: H04N 19/00 Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
• CPC Class Codes: H04N 19/90 using coding techniques not provided for in groups H04N19/10-H04N19/85, e.g. fractals

Abstract

A signal transmission method which reduces the frequency band of a transmission channel by sampling the input signal, quantizing each sampled pulse, combining the quantized pulses into a group of pulses, combining the quantized pulses in each group into a single pulse the quantized amplitude of which is uniquely determined from the quantized amplitude of each component pulse. The signal transmission method is used for transmitting video, facsimile, audio, data or other similar signals characterized by a high density of information with sufficient recognizability at a comparatively slight cost of signal-noise ratio.

Claims

1. A signal processing method comprising the steps of sampling an input signal at predetermined intervals to produce a succession of pulses, quantizing the amplitude of each pulse, combining every predetermined number of successive quantized pulses into a group of pulses in the sampled order, combining the quantized pulses in each group into a single pulse such that a quantized amplitude of the single pulse is uniquely determined from the quantized amplitude of each component pulse and the sampled order thereof in the group the quantized amplitude of each component pulse can be uniquely determined from the quantized amplitude of the single pulse and such that between two groups of quantized pulses which are respectively combined into two single pulses which differ from each other in quantized amplitude by one level, there exists only one component pulse which differs from its counterpart pulse in said group by only one level, the other component pulses and counterparts having the same amplitude level, and converting a succession of the single pulses into an amplitude-modulated signal through a low-pass filter.

2. A signal processing method as defined in claim 1, further comprising the steps of scanning a target to obtain said input signal, wherein the pulse interval of said sampling pulse is set at an exact division of the period Of said scanning.

3. A signal processing method comprising the steps of respectively sampling a plurality of input signals at predetermined intervals to produce successions of pulses, quantizing the amplitude of each sampled pulse, combining said plurality of sampled pulses into a group of pulses in predetermined order, combining the quantized pulses in each group into a single pulse such that a quantized amplitude of the single pulse is uniquely determined from the quantized amplitude of each component pulse and the order thereof in the group and the quantized amplitude of each component pulse can be uniquely determined from the quantized amplitude of the single pulse and such that between two groups of quantized pulses which are respectively combined into two single pulses which differ from each other in quantized amplitude by one level, there exists only one component pulse which differs from its counterpart pulse in said group by only one level, the other component pulses and counterparts having the same amplitude level, and converting a succession of single pulses into an amplitude-modulated signal through a low-pass filter.

4. A signal processing method as defined in claim 3, further comprising the steps of scanning a target to obtain one of said input signals, wherein the pulse interval of said sampling pulse is set at an exact division of the period of said scanning.

5. A signal processing method as defined in claim 3, further comprising the steps of scanning a target to obtain said input signal, and determining the position of the sampling pulse for sampling said input signal in relation to the timing of said scanning.

6. A signal processing method as defined in claim 5, further comprising the step of selecting a frequency of said sampling pulse to correspond to one half the product of the scanning frequency multiplied by an odd number, such that said product is in the range of from approximately two times as high as the maximum frequency of said input signals to approximately two times as high as the bank width of a transmission channel for said processed signal.

7. A signal processing method as defined in claim 5, further comprising the steps of causing the blanking periods of said input signals to substantially coincide with one another, and transmitting a synchronizing signal for said sampling pulse during said blanking period.

8. A signal transmission method as defined in claim 7, further comprising the steps of dividing a reference frequency which is substantially common to both sending and receiving systems of said signal processing method by a number n (an integer) to obtain said synchronizing signal which is transmitted from said sending system to said receiving system;

and selecting one pulse out of said number of said sampling pulses different in phase obtained by dividing said reference frequency by said number n, said selection being made with reference to said transmitted signal to be used as a timing reference in the said receiving system; and

renewing said selection of one pulse upon every arrival of said transmitted signal.

9. A signal transmission method characterized in sampling a signal having frequency band not broader than 2W and samplable by p (an integer number) quantum levels, with sampling pulses having pulse intervals of 1/4 W, separating the sampled signal into two sets of pulse sequences taken at every other sampling point, delaying at least one set of said two pulse sequences to cause the pulses in said two pulse sequences to coincide, converting said two pulse sequences to a signal having pulse intervals of 1/2 W and a quantized amplitude of p2, and transmitting said converted signal after modulation.