Temperature compensating circuit, temperature compensating logarithm conversion circuit and light receiver

Abstract

A temperature compensating circuit includes a first circuit network 1 between an inverting input terminal of an operational amplifier 13 and an output terminal of the operational amplifier 13, and a second circuit network 2 between the inverting input terminal of the operational amplifier 13 and a reference potential. At least one of the first circuit network and the second circuit network is made of an arrangement containing a plurality of series-connected thermistor/resistor pairs in which the thermistors are connected parallel to the resistors, and the temperature compensating circuit compensates a temperature-dependent signal which is inputted into a positive phase input terminal of the operational amplifier 13, and outputs the temperature-compensated signal.

What is claimed is:  
     
         1 . An optical signal receiver comprising: 
 a light receiving element to convert optical signals into electric signals;    an amplifier to amplify said electric signals converted from said optical signals; and    a bias circuit connected with said light receiving element,    wherein said light receiving element is an avalanche photodiode (APD) and said optical receiver includes an APD characteristic correction unit to correct input and output characteristics of said avalanche photodiode (APD).    
     
     
         2 . An optical signal receiver according to  claim 1 , wherein said amplifier comprises a preamplifier and a postamplifier.  
     
     
         3 . An optical signal receiver according to  claim 1 , wherein said optical signal receiver further includes a discriminating/reproducing device connected to said amplifier.  
     
     
         4 . An optical signal receiver according to  claim 2 , wherein said optical signal receiver further includes a-discriminating/reproducing device connected to said amplifier.  
     
     
         5 . An optical signal receiver according to  claim 3 , wherein said optical signal receiver further includes a timing producing device to extract a clock component.  
     
     
         6 . An optical signal receiver according to  claim 4 , wherein said optical signal receiver further includes a timing producing device to extract a clock component.  
     
     
         7 . An optical signal receiver according to  claim 5 , wherein said optical signal receiver further includes a light input signal interrupt detector to detect an interruption of light input and to output an alarm.  
     
     
         8 . An optical signal receiver according to  claim 6 , wherein said optical signal receiver further includes a light input signal interrupt detector to detect an interruption of light input and to output an alarm.  
     
     
         9 . An optical signal receiver comprising: 
 a light receiving element to convert optical signals into electric signals;    an amplifier to amplify said electric signals converted from said optical signals;    a bias circuit connected with said light receiving element; and    a logarithmic converter to monitor a reception intensity of said optical signals;    wherein said light receiving element is an avalanche photodiode (APD) and said optical receiver includes an APD characteristic correction unit to correct input and output characteristics of said avalanche photodiode (APD).    
     
     
         10 . An optical signal receiver according to  claim 9 , wherein said amplifier comprises a preamplifier and a postamplifier.  
     
     
         11 . An optical signal receiver according to  claim 9 , wherein said optical signal receiver further includes a discriminating/reproducing device connected to said amplifier.  
     
     
         12 . An optical signal receiver according to  claim 10 , wherein said optical signal receiver further includes a discriminating/reproducing device connected to said amplifier.  
     
     
         13 . An optical signal receiver according to  claim 11 , wherein said optical signal receiver further includes a timing producing device to extract a clock component.  
     
     
         14 . An optical signal receiver according to  claim 12 , wherein said optical signal receiver further includes a timing producing device to extract a clock component.  
     
     
         15 . An optical signal receiver according to  claim 13 , wherein said optical signal receiver further includes a light input signal interrupt detector to detect an interruption of light input and to output an alarm.  
     
     
         16 . An optical signal receiver according to  claim 14 , wherein said optical signal receiver further includes a light input signal interrupt detector to detect an interruption of light input and to output an alarm.