Edwin Armstrong and Frequency Modulator (United States of America 1983)

21 September (United States of America ) within release American Inventors Issue goes into circulation Stamp Edwin Armstrong and Frequency Modulator face value 20 United States cent

Stamp Edwin Armstrong and Frequency Modulator in catalogues
Michel:	Mi:US 1654
Stamp Number:	Sn:US 2056

Stamp is square format.

Also in the issue American Inventors Issue:

• Se-tenant - American Inventors Block of 4 face value 20;
• Se-tenant - American Inventors face value 4*20;
• Stamp - Charles Steinmetz and Curve on Graph face value 20;
• Stamp - Edwin Armstrong and Frequency Modulator face value 20;
• Stamp - Nikola Tesla and Induction Motor face value 20;
• Stamp - Philo T. Farnsworth and First Televison Camera face value 20;