Most Popular Articles
Determine AM Modulation with an Oscilloscope
The table below allows you to easily determine the modulation level
of an AM transmitter. Connect an RF sample to the horizontal input of
an oscilloscope and set the peak-to-peak (pk-pk) unmodulated carrier
level to occupy two divisions. Then apply modulation and read the
peak-to-peak level. Find the nearest number in the scope division
column below and read the modulation percentage from the left-most
column of the same row.
|Modulation (%)||Sideband Power (dbc)1||Scope Divisions|
1 - The power in each sideband relative to the carrier power (dBc), is determined by
Pssb = 10log(Pssb/Pc), where Pssb is the power in a single sideband, and Pc is the carrier power.
The power in a single sideband is equal to one-half the modulation power. Modulation power is determined by
Pm = m2(Pc)/2, where Pm is the modulation power, m is the modulation index (percentage expressed as a decimal), and Pc is the carrier power.
Source: The AM Window
Acceptable Use Policy blog comments powered by Disqus
[an error occurred while processing this directive]
Today in Radio History
The history of radio broadcasting extends beyond the work of a few famous inventors.
Read each issue online in our Digital Edition Format in your Web browser.
EAS Information More on EAS
The feed provides feeds for all US states and territories.
Need a calendar for your computer desktop? Use one of ours.
Information from manufacturers and associations about industry news, products, technology and business announcements.
When building its new broadcast production vehicle, MRN applied lessons learned from the past.
Browse Back Issues[an error occurred while processing this directive]
Also in the April Issue
- Update on Transmitters
- On-air Missteps to Avoid
- Tower Lease Renegotiation
- New Products
- Applied Technology: Streaming with the MPEG HE-AAC Audio Codec
- Side by Side: Studio Furniture
- Practical Use: Circulators and Isolators