The Fluke 5200 AC calibrator contains such a precision high speed rectifier / AC-DC converter.
Have a look into the manual and schematics, which effort that 10Hz - 1 MHz design requires. More modern components might simplify the circuitry.
Frank
Thank you for the tip, Frank. That manual is beautiful and humbling at the same time. It uses an opamp+diode scheme to do the rectification, although I'm having trouble understanding all the discrete circuitry that comprises the amplifier. As you said, however, all that mess should be unnecessary with modern parts. I guess it was done differently back then; you had to make do with what you had.
I had previously written off this method as inaccurate, but I've done some more simulations and come the following conclusions:
1) The reverse recovery time of the rectifier diodes must be very short (or zero with schottky diodes).
2) The junction capacitance of the diodes, which is typically higher with schottkys, must be compensated for by using smaller resistance values in the feedback network, on the order of 100 ohms or less for BAT54s, for example. Otherwise the capacitance begins to dominate the behavior of the diode at high frequencies and it doesn't rectify anymore.
So, obtaining a high speed opamp with the capability to drive low impedances isn't difficult, but I could use some advice in selecting appropriate rectifier diodes. Maybe I should look into RF diodes, perhaps? LTSpice indicates the 1N4148 has a significant 20ns recovery time, which results in approximately 1% error at 1MHz.
Here is the HP 410 meter. Thought it would be interesting to look at. My friend Roni at M.U. used to make those input diodes. Still has a few around the shop.
Amazing. "These design considerations have resulted in the rectifier tube and it's circuitry having a resonant frequency of approximately 1500 megacycles." 1.5GHz seems impressive even by today's standards. I also can't wait to use the unit "micromicrofarad" while talking to my graduate advisor.