Electronic musical instrument of time division multiplexed type

In an electronic muscial instrument having a single keyboard with keys separated into a lower key range and a higher key range in accordance with corresponding note pitch, and having a key coder which scans the keyboard and sequentially provides, during time slots of each scanning cycle, key codes identifying depressed keys, the improvement comprising:

• key range detection means for detecting from the key codes provided in each time slot the key range containing the corresponding depressed key, and for gating out the key codes for keys in a certain one of said key ranges during one portion only of each of the corresponding time slots, said one portion being less than the entire time slot,
• time shared tone generator means, connected to said key range detection means, for providing musical tones corresponding to each of the key codes gated out in said one portion of said corresponding time slots,
• priority key detection means, cooperating with said key range detection means, for determining the one time slot containing the key code for a key of certain predetermined priority amongst the depressed keys in said one key range, and for gating out that key code during the remaining portion of the time slot containing that key code, and
• register and monophonic tone generator means, connected to said priority key detection means and responsive only to a key code gated out in said time slot remaining portion, for generating a musical tone corresponding thereto.

An electronic musical instrument comprising:

• key switches corresponding to keys arranged in a certain order;
• depressed key detection means for detecting on-off states of said key switches to deliver, during sequential time slots of a scanning cycle, key data of depressed keys in the order of arrangement of said keys;
• specific key detection means for detecting the one time slot in which key data of the specific key of a predetermined priority among the depressed keys is delivered;
• gate means for gating out said delivered key data of depressed keys from said depressed key detection means only during one portion of each of said time slots, said one portion being less than the whole of said time slot, and for gating out, during the remaining portion of only said one time slot detected by said specific key detection means, the key data of said specific key;
• a processing unit for processing the key data gated out of said gate means during said one portion of said each time slot to output it as first key data, and processing the key data of the specific key gated out of said gate means during said remaining portion of said only time slot detected by said specific key detection means to output it as second key data;
• a first musical tone generation circuit for generating musical tones in response to said first key data;
• and
• a second musical tone generation circuit for generating musical tones in response to said second key data.