10W SSB Mixer Circuit

The NE602 single chip contains the mixer and the main parts that can be used as a local oscillator. It is an 8-pin DIP package. NE602AD and NE602AN are improved new versions of IC.

The frequency converter in NE602 is a GTC (Gilbert Transconductance Cell), which has the function of mixing, but is better than the double-balanced frequency converter (DBM). GTC is so easy to use that it is not difficult to find traces of GTC in various frequency multipliers and amplitude modulators.

GTC is very different from the variable balanced mixer composed of diodes. GTC is composed of active components such as transistors. Its advantage is that it has high sensitivity and can process signals as low as microvolts (uV).

This figure shows the SSB mixer circuit composed of the common NE602. C1, C2, C3, RFC, JT and the internal oscillator circuit of NE602 form the VXO circuit, and the generated local oscillator signal is sent to the mixer. The USB signal with a frequency of 10.700MHz and a maximum amplitude level of no more than 68mV (measured on pin 1 of NE602) sent from the previous stage is also sent to the mixer and finally output after filtering.