637应用电路
dB CALIBRATION
Refer to Figure 20:
• Set V
= 1.00 V 1.00 V IN
• Adjust R1 for 0 dB out = 0.00 V
• Set V = 0.1 V dc or 0.10 V rms IN
• Adjust R2 for dB out = −2.00 VAny other dB reference be used by setng VIN and R1 cordingly.
As with previous monolithic rms converters from Devices, Inc., the AD637 has an auxiliary dB output avlable to users. The logarithm of the rms output signal is brought out to a separate n, allowing direct dB measurement with a useful range of 60 dB. An externally progmed reference current allows the user to select the 0 dB reference voltage to correspond to any level between 0.1 V and 2.0 V rms.
