in addition , according to the second aspect of the invention , it is possible to use a digital signal processor corresponding to the difference in the image processing type of the scope irrespective of whether not the scope is a type equipped with a timing generator , and excellent image processing is made possible even if there is the difference between the primary color system the complementary color system , a difference in the number of pixels , and so forth in the imaging devices . fig1 , 2 a , and 2 b show the configuration of an electronic endoscope apparatus in accordance with an embodiment of the invention . fig1 shows the configuration of a processor unit ( main unit ), and fig2 a and 2b show configurations of a type and b type scopes ( electronic endoscopes ), respectively . first , as shown in fig2 a , an a type scope 1 a is not equipped with a timing generator and has a ccd 2 a , a correlated double sampling ( cds )/ automatic gain control ( agc ) circuit 18 a , and a read - only memory ( rom ) or a microcomputer or the like 20 a , and a video signal is outputted as an analog signal . in addition , as shown in fig2 b , a b type scope 1 b is equipped with a timing generator ( tg ) 21 , has a ccd 2 b , a cds / agc circuit 18 b , an a / d converter 22 , and a rom 20 b , and a video signal is outputted as a digital signal . it should be noted that the a type scope 1 a and the b type scope 1 b are connected to a processor unit 23 by means of connector portions ( connector - and processor unit - side connector receivers ) 24 a and 24 b of different shapes so as to discriminate the two scopes 1 a and 1 b and prevent erroneous connection . in fig1 , in the processor unit 23 , one client circuit board 26 is connected to a secondary circuit board 28 via an isolator ( pulse transformer , photocoupler , or the like ) 27 . a timing generator ( tg ) 30 corresponding to the aforementioned a type scope 1 a , a first ( image ) signal processing unit 31 having an a / d converter and the like and adapted to effect video processing of an output signal from the a type scope 1 a , and a second signal processing unit 32 having a buffer circuit and the like and adapted to effect video processing of an output signal from the b type scope 1 b are provided on the client circuit board 26 . in addition , a d 1 type digital signal processor ( dsp ) 33 and a d 2 type dsp 34 are respectively connected to the first signal processing unit 31 and the second signal processing unit 32 . in addition , the client circuit board 26 is provided with a front cpu ( or a microcomputer ) 36 and a dsp - use cpu 37 . this front cpu 36 effects communication with the roms ( or microcomputers ) 20 a and 20 b on the sides of the scopes 1 a and 1 b to determine the types ( presence or absence of the tg , the type of dsp used , etc .) of the scopes 1 a and 1 b , and turns on and off the power supply of the timing generator 30 , the first signal processing unit 31 , and the second signal processing unit 32 . the dsp - use cpu 37 , upon receiving a dsp selection instruction signal from the front cpu 36 , turns on and off the first dsp 33 and the second dsp 34 . namely , as for the scopes 1 a and 1 b , the type of dsp used is determined by the characteristics and type of an imaging device , i . e ., by the type of image processing , irrespective of the presence or absence of the tg , and either corresponding dsp ( 33 , 34 ) is selected . the embodiment has the above - described configuration . as shown in fig1 , the electronic endoscope apparatus in accordance with the invention is so configured as to be able to connect the plurality of scopes 1 a and 1 b to the processor unit 23 by means of the connector portions 24 a and 24 b having different shapes . when either one of these scopes 1 a and 1 b is connected , the operation shown in fig3 is executed by the front cpu 36 and the dsp - use cpu 37 . in fig3 , first , the front cpu 36 effects communication with the roms 20 a and 20 b in the scopes 1 a and 1 b ( step 101 ). in an ensuing step 102 , the type of the connected scope is discriminated , and if it is determined here that the scope is the a type scope 1 a , the operation proceeds to step 103 . in step 103 , the front cpu 36 turns on ( the power supply of ) the timing generator 30 and the first signal processing unit 31 and turns off ( the power supply of ) the second signal processing unit 32 . then , in step 104 , the type of the scope dsp is discriminated , and if it is determined here that the type of the scope dsp is the d 1 type , the operation proceeds to step 105 . in step 105 , an instruction signal is outputted to the dsp - use cpu 37 to turn on the d 1 type dsp 33 and turn off the d 2 type dsp 34 . as a result , the dsp - use cpu 37 turns on the d 1 type dsp 33 and turns off the d 2 type dsp 34 ( step 106 ). if it is determined in the aforementioned step 104 that the type of the scope dsp is the d 2 type , the operation proceeds to step 107 . in step 107 , an instruction signal is outputted to the dsp - use cpu 37 to turn off the d 1 type dsp 33 and turn on the d 2 type dsp 34 . as a result , the dsp - use cpu 37 turns off the d 1 type dsp 33 and turns on the d 2 type dsp 34 ( step 108 ). meanwhile , if it is determined in the aforementioned step 102 that the connected scope is the b type scope 1 b , the operation proceeds to step 110 , in which the front cpu 36 turns off the timing generator 30 and the first signal processing unit 31 and turns on the second signal processing unit 32 . then , in step 111 , the type of the scope dsp is discriminated , and if it is determined here that the type of the scope dsp is the d 1 type , the operation proceeds to step 112 . in step 112 , an instruction signal is outputted to the dsp - use cpu 37 to turn on the d 1 type dsp 33 and turn off the d 2 type dsp 34 . as a result , the dsp - use cpu 37 turns on the d 1 type dsp 33 and turns off the d 2 type dsp 34 ( step 113 ). if it is determined in the aforementioned step 111 that the type of the scope dsp is the d 2 type , the operation proceeds to step 114 . in step 107 , an instruction signal is outputted to the dsp - use cpu 37 to turn off the d 1 type dsp 33 and turn on the d 2 type dsp 34 . as a result , the dsp - use cpu 37 turns off the d 1 type dsp 33 and turns on the d 2 type dsp 34 ( step 115 ). when the a type scope 1 a is thus connected , a ccd drive signal is supplied to the ccd 2 a by using the timing generator ( tg ) 30 on the client circuit board 26 , whereby an image pickup signal is outputted from the ccd 2 a . this image pickup signal is processed by the cds / agc circuit 18 a , and an analog video signal is outputted from the scope 1 a to the processor unit 23 . then , this analog video signal is converted to a digital video signal by the first signal processing unit 31 , and this digital video signal is processed by either the d 1 type dsp 33 or the d 2 type dsp 34 . an output of this dsp 33 or 34 is outputted to a monitor through signal processing in the secondary circuit board 28 , thereby displaying on the monitor an image ( video image ) of the object to be observed . meanwhile , when the b type scope 1 b is connected , a ccd drive signal is supplied to the ccd 2 b by using the timing generator ( tg ) 21 on the in the scope 1 b , whereby an image pickup signal is outputted from the ccd 2 b . this image pickup signal is processed by the cds / agc circuit 18 b and the a / d converter 22 , and a digital video signal is outputted from the scope 1 b to the processor unit 23 . then , this digital video signal is subjected to buffer processing by the second signal processing unit 32 , and this digital video signal is processed by either the d 1 type dsp 33 or the d 2 type dsp 34 , thereby displaying on the monitor an image of the object to be observed through the processing by the secondary circuit board 28 . although in the above - described embodiment both the front cpu 36 and the dsp - use cpu 37 were used , control of the turning on and off of the power supply of the dsps 33 and 34 may be effected by using only the front cpu 36 without using this dsp - use cpu 37 . according to this arrangement , it is possible to attain a cost reduction . according to the electronic endoscope apparatus in accordance with the invention , advantages are obtained in that both the scope equipped with the timing generator and the scope not equipped therewith can be used by being connected to a single processor unit , that it is possible to form an excellent image by high - speed drive signals corresponding to highly pixilated imaging devices , and that cost reduction also becomes possible . the entire disclosure of each and every foreign patent application from which the benefit of foreign priority has been claimed in the present application is incorporated herein by reference , as if fully set forth .
an electronic endoscope apparatus comprises a processor unit so as to allow an a type scope not having a timing generator and a b type scope having a timing generator to be connector - connected to the processor unit . the electronic endoscope comprises : an in - client - circuit timing generator and a first image signal processing unit both corresponding the a type scope ; and a second image signal processing unit corresponding to the b type scope , wherein control is provided such that when the a type scope is connected to the processor unit , the in - client - circuit timing generator and the first image signal processing unit are operated , whereas when the b type scope is connected to the processor unit , the second image signal processing unit is operated .