MODEL 121
PAR"Lock-In Amplifiers Recover Low-Level Signals from Noise
MODEL 120
Model 120 is a fixed frequency unit which allows the benefits of phase sensitive detection to be achieved at an economical price. Representative specifications are: FREQUENCY RANGE: 5 Hz to 150 kHz. Frequency is determined by two plug-in circuit boards, each of which contains two or four [depending upon frequency) resistors and two capacitors. Plug-in frequency determining boards for any particular frequency in the above range can be ordered from PAR or the user can change frequency by changing the resistors and capacitors on the two plug-in circuit boards. A front panel vernier adjustment functions as a fine frequency control. SIGNAL INPUT C H A R A C T E R I S T I C S : Singleended input of 10 Megohms shunted by 30 pF. Selectivity characteristic is that of a parallel reso nant circuit with a Q of approximately 10. SENSITIVITY: 100 i
