05-15-2023-2012 - In June 1928, the General Radio 403 was the first commercial signal generator ever marketed. It supported a frequency range of 500 Hz to 1.5 MHz.[2] Also, in April 1929, the first commercial frequency standard was marketed by General Radio with a frequency of 50 KHz.[3]

History

In June 1928, the General Radio 403 was the first commercial signal generator ever marketed. It supported a frequency range of 500 Hz to 1.5 MHz.^[2] Also, in April 1929, the first commercial frequency standard was marketed by General Radio with a frequency of 50 KHz.^[3] 

https://en.wikipedia.org/wiki/Signal_generator