Discriminator for discriminating employed modulation technique, signal demodulator, musical instrument and method of discrimination

A signal demodulator for reproducing a signal from a modulated signal, a carrier signal being modulated to said modulated signal with said signal through a modulation technique, comprising:

• a discriminator supplied with said modulated signal dividable into plural portions each equal in time period to a modulation period, each of said plural portions having a modulated section subjected to a modulation through said modulation technique and followed by a non-modulated section, and including
• an information processor having information processing capability and
• a sampler extracting discrete values from a waveform of said modulated signal so as to produce a series of samples expressing said discrete values and supplying said series of samples to said information processor,
• a computer program running on said information processor so as to realize
• a detector supplied with said series of samples from said sampler, and specifying groups of samples expressing the non-modulated sections in said plural portions,
• a measurer supplied with said groups of samples from said detector, and determining a time period between the group of samples in one of said plural portions and the group of samples in another of said plural portions next to said one of said plural portions and
• a determiner determining that said modulation technique is same as a predetermined modulation technique when said time period is equal to said modulation period;
• and
• a signal demodulating module connected to said discriminator, and supplied with said modulated signal so as to demodulate said modulated signal to said signal through a demodulating technique corresponding to said predetermined modulation technique when said determiner determines that said modulation technique is same as said predetermined modulation technique.

A musical instrument for producing tones, comprising:

• a signal demodulator for reproducing a music signal expressing tones to be produced from a modulated signal, a carrier signal being modulated to said modulated signal with said music signal through a modulation technique, and including
• a discriminator supplied with said modulated signal dividable into plural portions each equal in time period to a modulation period, each of said plural portions having a modulated section subjected to a modulation through said modulation technique and followed by a non-modulated section, and having
• an information processor having information processing capability and
• a sampler extracting discrete values from a waveform of said modulated signal so as to produce a series of samples expressing said discrete values and supplying said series of samples to said information processor,
• a computer program running on said information processor so as to realize
• a detector supplied with said series of samples from said sampler, and specifying groups of samples expressing the non-modulated sections in said plural portions,
• a measurer supplied with said groups of samples from said detector, and determining a time period between the group of samples in one of said plural portions and the group of samples in another of said plural portions next to said one of said plural portions and
• a determiner determining that said modulation technique is same as a predetermined modulation technique when said time period is equal to said modulation period and
• a signal demodulating module connected to said discriminator, and supplied with said modulated signal so as to demodulate said modulated signal to said music signal through a demodulating technique corresponding to said predetermined modulation technique when said determiner determines that said modulation technique is same as said predetermined modulation technique;
• and
• a tone generator connected to said signal modulator, and supplied with said music signal so as to produce said tones on the basis of said music signal.

A method of discriminating a modulation technique through which a signal is modulated to a modulated signal dividable into plural portions each equal in time period to a modulation period, each of said plural portions having a modulated section subjected to a modulation through said modulation technique and followed by a non-modulated section, comprising the steps of:

• a) extracting discrete values from a waveform of said modulated signal so as to produce a series of samples expressing said discrete values;
• b) specifying groups of samples expressing the non-modulated sections in said plural portions;
• c) determining a time period between the group of samples in one of said plural portions and the group of samples in another of said plural portions next to said one of said plural portions;
• and
• d) determining that said modulation technique is same as a predetermined modulation technique when said time period is equal to said modulation period.