TFK U2343

This chip is nice because there is no separation adjustment.
P is for adjusting the VCO.
In Sweden at Kjell & Co article no. 90464

THD at 1 kHz mono

THD at 1 kHz stereo


Frequency characteristic - the 19 kHz interferes at the high end.
The de-emphasis capacitors on the outputs have been changed from 15 nF to 12+2,2 nF (=14,4 nF)

Channel separation.
The roll off above 2 kHz is due to the low-pass filter (HP5489A) at the outputs in order to eliminate interference from the 19 kHz.

Frequency spectrum without modulation.
19 kHz and 57 kHz are quite high and a low pass filter is recommended.

Frequency spectrum with 1 kHz signal