I am building a peak program meter for my tape machine.
The circuit consist of a precison rectifier and display circuits for LEDs etc.
I have a general question regarding the rectifier circuit, which has the program as an input and produces a varying DC output which is then displayed and used to record at the proper level. This circuit has the proper attack and decay times which makes the whole thing a peak program meter and not the regularly used VU meter.
Here is my problem:
I feed an audio signal at a certain voltage into the rectifier and measure the DC output the circuit produces. The output varies slightly with frequency.
At 60 Hz and 3 V rms I get a rectified signal of 4.01 volt (and not 4.24 as I would have expected, 3V/0.707). As I go up with the frequency the output decreases to about 3.7V at 20,000 Hz.
Is my assumption that for a pure sine wave the relation Vpeak=Vrms/0.707 holds regardless of frequency correct?
If that is true there must be something wrong with the circuit or the design.
Help anybody??
Uwe
The circuit consist of a precison rectifier and display circuits for LEDs etc.
I have a general question regarding the rectifier circuit, which has the program as an input and produces a varying DC output which is then displayed and used to record at the proper level. This circuit has the proper attack and decay times which makes the whole thing a peak program meter and not the regularly used VU meter.
Here is my problem:
I feed an audio signal at a certain voltage into the rectifier and measure the DC output the circuit produces. The output varies slightly with frequency.
At 60 Hz and 3 V rms I get a rectified signal of 4.01 volt (and not 4.24 as I would have expected, 3V/0.707). As I go up with the frequency the output decreases to about 3.7V at 20,000 Hz.
Is my assumption that for a pure sine wave the relation Vpeak=Vrms/0.707 holds regardless of frequency correct?
If that is true there must be something wrong with the circuit or the design.
Help anybody??
Uwe