according to fig1 , the apparatus includes a measuring device 1 , which is typically a pulse meter attached to the chest by a flexible belt . the pulse meter in question contains electrodes , with the aid of which the pulse of the person is measured . the measuring device 1 can naturally be some other measuring device , such as a manometer of a compressed - air bottle in diving equipment , or alternatively a blood - pressure meter . the measuring device is connected to a transmitter / coder 2 , in which the measurement signal is edited into a transmittable form and given a code individuating the transmitter 2 . the signal is sent from the transmitter 2 wirelessly over a transfer path 3 to a receiver 4 , which also includes means for decoding the code . the transfer path 3 is typically the air between the measuring device 2 located around the chest and a receiver located on the wrist , or alternatively the water between a transmitter attached to the compressed - air bottle and the wristop computer . the receiver 4 is , in turn , connected to a data - processing unit 5 , to which a display is typically also connected . the receiver 4 and the data - processing unit 5 are typically implemented in a wristop computer , which is reminiscent of a wristwatch . such a wristop computer can include not only pulse - measuring properties or other measuring properties , but also normal clock functions , possible positioning equipment , such as gps circuits , and an altimeter , in which the sensor is typically a pressure sensor , for example , a capacitive pressure sensor . the wristop computer can also include , for example , a temperature measuring device . wristop computers are also known , which have connections and data communications devices for connecting a wristop computer to a normal microcomputer , for example , through a usb bus . according to fig2 a , the signal being transmitted includes two repeating time periods , a time period t 1 and a time period t 2 , of which the time period t 1 contains the actual measurement information , either directly as the length of the time period , or proportional to the length of this . in the pulse measurement application , t 1 is either directly the time between the pulses , or else a time proportional to this . for example , in a pressure measurement application , t 1 can also be a period of time proportional to the pressure ( the pressure in an oxygen bottle , or blood pressure ). the time period t 2 , in turn , includes a signal identification code , a codeword 15 , and a start bit 10 , which , according to the invention , is a powered pulse , with a digital value of 1 . this is followed by the desired number of code pulses ( bits ) as a codeword 15 , of which , according to one preferred embodiment of the invention , at most 50 % contain energy , in other words , have a value of 1 . the other bits have a value of 0 . in fig2 a , the pulses 11 and 12 represent these energy - containing pulses in an 8 - bit codeword 15 . the pulse 11 is the second and the pulse 12 the eighth in the code work 15 in question . the number of code bits (= the length of the codeword ) can naturally be more or less , however , the number of bits in the codeword 15 typically varies from 4 to 128 . thus , the transmitter &# 39 ; s transmission power is on during the pulses 11 and 12 while transmission power is not used during time between these 1 - bits . thus , in the solution of fig2 a , in an eight - bit codeword , the transmission power is on for 25 % of the duration of the code . the same principle in terms of power consumption naturally also applies to the time period t 1 between the pulses 10 and 12 , which represents analog data . thus , transmission power is not used at all in the time period t 1 . thus , t 1 can contain , as an analog value , data , for example , on pulses , the periods between pulses , the pressure of an oxygen bottles , pedalling cadence , blood pressure , or speed . at the receiver end , t 1 is thus converted into data depicting the variable being measured , by defining the time period t 1 as an analog variable , for example with the aid of a gate circuit , during the time between the pulses 10 and 12 . in fig2 a , the first time periods t 1 and t 2 are followed by second time periods t 1 ′ and t 2 , of which t 1 ′ in longer than the time period t 1 . in turn , fig2 b shows , a second alternative solution according to the invention . in this , three bits in a 1 state , which depict the pulses 11 , 12 , and 13 , are used in the time period t 2 for coding . in the solution of fig2 b , during the codeword 15 , transmission power is on for 37 . 5 % of the duration of the codeword . according to the invention , the time period t 1 or t 1 ′ can contain data , for instance , on the pressure in a compressed air bottle , or on blood pressure , or on other information used or processed by the wristop computer . alternatively , instead of the time periods t 1 or t 1 ′, the time period data being measured can be the sum t 3 of the time periods t 1 and t 2 , or the sum t 3 ′ of the time periods t 2 and t 1 ′, in which case the time t 2 used for transmitting the codeword 15 and the start bit is also included in the time period measured . fig3 a – 3 c show various alternatives of the use of 1 - bits in a 16 - bit codeword 15 . the sequence number of each bit is marked on the time line t . in the example 3 a , the bits 2 , 3 , 5 , 9 , and 16 have a value of 1 . correspondingly , in fig3 b , the bits 1 , 3 , 13 , 14 , and 16 have a value of 1 . similarly , in fig3 c , the 1 - bits are the bits 1 , 13 , 14 , 15 , and 16 . in some applications ( pressure measurement ), the measurement period can start with the period t 2 containing the identifier code 15 . thus , according to the invention , the power used for transmission is intended to be minimized by avoiding the transmission of pulses containing power . thus , even in negative coding ( containing 0 - bit power ) the intention is to similarly avoid bits containing power . according to the invention , there can even be several consecutive digital codewords 15 , one can be , as such , the identifier individuating the transmitting device , the second can be a code stating the type of measurement signal ( e . g ., acceleration , pulse , etc . ), the third can be , for example , error correction , or an error - detection code , which is calculated in a specific manner from the other codes . the invention being thus described , it will be obvious that the same may be varied in many ways . such variations are not to be regarded as a departure from the spirit and scope of the invention , and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims .
a method and apparatus in connection with a wristop computer . according to the method , a desired variable is measured using a measuring unit , the measured variable is equipped with at least one digital codeword and transmitted wirelessly over a transfer channel to a receiver , and at the other end of the transfer channel , the transmitter &# 39 ; s signal is identified on the basis of at least one codeword . according to the invention , the digital codeword is transmitted to the receiver together with the measured variable depicted as time - period data .